7pm: One person has been killed and four injured in a crane accident at Fukushima No. 2 power plant, the International Atomic Energy Agency says. And the UN's nuclear watchdog said at Fukushima No. 1 power plant, which suffered an explosion on Saturday a day after the massive quake, and where authorities are battling a feared meltdown of two reactors, eight workers had been affected. "Four workers were injured by the explosion at the Unit 1 reactor, and there are three other reported injuries in other incidents," the IAEA said on its website, citing Japanese authorities. "In addition, one worker was exposed to higher-than-normal radiation levels that fall below the IAEA guidance for emergency situations," it said, without giving further details.

6.35pm: Japan's Meteorological Agency says it has upgraded the magnitude of Friday's catastrophic earthquake to 9.0. The agency earlier measured it at 8.8. The quake was already the biggest to hit Japan since record-keeping began in the late 1800s and one of the biggest ever recorded in the world. The US Geological Survey has measured the quake at magnitude 8.9, and that number remains unchanged.

6.25pm: Hino Motors and Mitsubishi Motors will temporarily suspend production at their domestic plants due to uncertainty over the procurement of auto parts, according to the Kyodo News Agency. The companies will suspend production from Monday, joining other automakers including Toyota and Honda.

6.19pm: Prime Minister Naoto Kan has instructed the president of Toshiba, maker of the troubled reactors at the nuclear power plants in quake-hit Fukushima Prefecture, to do all he can to contain the problems at the plants.

5.42pm: Search and rescue teams are arriving in Japan, with more than 70 countries and international organisations offering to provide support. The Japanese Foreign Ministry said Tokyo received offers for support from 69 countries and regions along with five international organisations.

5.30pm: The Japanese government has urged large companies to limit electricity use amid fears of possible supply disruptions, the Kyodo News Agency reports.

5.05pm: The Green Party has extended its condolences to the people of Japan. "Our heartfelt sympathies go out to the Japanese for the devastation and loss of life following the earthquake and tsunami," Green Party Co-leader Metiria Turei said today. "Our thoughts and prayers are also with all those families and friends here in New Zealand. "We will do everything to support the Japanese community here through this difficult time. "And to the people of Sendai especially, all of New Zealand stands with you. Kia kaha."

4.44pm: More than 200 bodies have been found at a new site in northeast Japan. "We have received a preliminary report that more than 200 bodies were found in the city of Higashimatsushima," a National Police Agency spokesman said, adding that local police are starting to collect the bodies.

4.17pm: Japan's US ambassador Ichiro Fujisaki has told CNN a partial meltdown occurred at the Fukushima plant. "There was a partial melt of a fuel rod, melting of fuel rod. There was a part of that... but it was nothing like a whole reactor melting down," said Fujisaki, adding that he was being briefed hourly on the situation.

4.15pm: Japan's earthquake appears to have moved the island by about eight feet (2.4 m), the US Geological Survey says. "That's a reasonable number," USGS seismologist Paul Earle told AFP. "Eight feet, that's certainly going to be in the ballpark." He said similar movements would have been seen for Chile and Indonesia.

4.11pm: Chief cabinet secretary, Yukio Edano, says it's likely a meltdown has taken place at the No.1 reactor at Fukushima Daiichi. "We do believe that there is a possibility that meltdown has occurred. It is inside the reactor. We can't see. However, we are assuming that a meltdown has occurred." Authorities are concerned over the possibility of meltdowns at the second and third reactors, he said. A meltdown occurs when the reactor core fails, with potential for widespread radiation.

4pm: A team of 48 search and rescue staff from New Zealand are expected to be on the ground in Japan tomorrow but it's still unclear where they'll be deployed. An advance party from the team is expected in japan this afternoon. Christchurch fire service area manager Dan Coward said the team would be made up of search and rescue staff from across New Zealand and includes some from Christchurch. The team is taking 15 tonnes of equipment which is being sent over on a mixture of Defence Force and commercial flights. Mr Coward was confident there would be no adverse effects on the continuing recovery operation in Christchurch. There are still two full taskforces of 48 each remaining here. He said the team took pride in being able to assist a nation which had provided support in Christchurch's time of need.

3.55pm: Fresh water is being injected into the No. 3 reactor of Fukushima No. 1 plant after it lost its cooling ability. Government spokesman Yukio Edano said radiation at that reactor was under control.

3.15pm: Nineteen more people have been exposed to radiation in addition to the three reported earlier, the Kyodo News Agency says. Meanwhile, an estimated 200,000 people have been evacuated so far from the areas around the Fukushima No.1 and No. 2 nuclear plants, according to the UN atomic watchdog.

3pm: Japan has been shaken by a strong earthquake off its eastern coast, closer to Tokyo than the massive quake that hit on Friday. The latest temblor swayed buildings in the capital. The US Geological Survey says the temblor had a magnitude of 6.2 and struck at 10.26am local time. It was centred about 179km east of Tokyo, at a depth of 24.5km. Japan has been rattled by more than 150 aftershocks since Friday.

2.51pm: Nuclear plant operator Tokyo Electric Power says radiation levels have surpassed the legal limit at Fukushima No. 1 plant.

1.47pm: Prime Minister Naoto Kan is planning to double the number of defence relief personnel to 100,000.

1.39pm: The death toll is nearing 900, Japanese police say. The National Police Agency said 688 people had been confirmed dead and 642 missing, with 1,570 injured in the disaster. Police in Sendai, Miyagi prefecture, separately said Friday that at least 200 and up to 300 bodies had been found on the shore.

1.19pm: Australia is calling for urgent information from Japan on the threat posed by an explosion at Fukushima nuclear plant and says it has offered Tokyo atomic expertise. Foreign Minister Kevin Rudd said Australia and the world was awaiting further information. "We and the rest of the international community need urgent briefings on the precise status of these reactors," he told public broadcaster ABC on Sunday. "We are seeking further co-operation on the technical and safety aspects of these from the Japanese government." Meanwhile, two Queensland search and rescue dog teams just back from Christchurch will fly to Japan today to search for survivors.

1pm: It has been confirmed that 1159 Australians in Japan are safe, including four in Sendai, the seaside city badly hit by the tsunami. The number of Australians registered with the embassy is 2319, and of these 189 are in affected areas.

12.52pm: US nuclear experts say pumping sea water to cool a quake-hit nuclear reactor is an "act of desperation" that may foreshadow a Chernobyl-like disaster. "The situation has become desperate enough that they apparently don't have the capability to deliver fresh water or plain water to cool the reactor and stabilise it, and now, in an act of desperation, are having to resort to diverting and using sea water," said Robert Alvarez, who works on nuclear disarmament at the Institute for Policy Studies. Peter Bradford, former head of the US Nuclear Regulatory Commission, said that if the cooling attempts fail, "at that point it's a Chernobyl-like situation where you start dumping in sand and cement."

12.40pm: Tokyo Disneyland and Tokyo Disney Sea, Japan's most popular amusement facilities, have been closed to carry out emergency safety checks. The operator told the Kyodo News Agency the closure will probably last about 10 days. A number of concerts, musicals, kabuki plays, exhibitions and other events across the nation have also announced cancellations.

12.30pm: California is closely monitoring efforts to contain leaks from a quake-damaged Japanese nuclear plant, as experts said radiation could be blown out across the Pacific. While officials downplayed any immediate danger, the US Nuclear Regulatory Commission deployed two experts to Japan.

12.04pm: A senior nuclear and industrial safety official says a meltdown may be underway at one of the Fukushima Dai Ichi nuclear power reactors, with there being potential for a widespread release of radiation.

Toshiro Bannai told CNN he was confident that an ensuing crisis could be controlled.

The Tokyo Electric Power Company said a second reactor at the plant failed early this morning. It said it was having trouble cooling the reactor and it may need to release radioactive steam to relieve the pressure.

11.53am: A former US energy policy adviser says the use of seawater and boron to cool the reactor at the Fukushima Dai Ichi nuclear power plant was a desperate, "Hail Mary pass" tactic, with success depending on the volume and rate at which the dousing continues.

Robert Alvarez told reporters in the US that the effort would need to continue non-stop for several days.

11.35am: Lights were switched off overnight at some of Japan's best-known landmarks in a bid to save electricity.

Kyodo News reported that the Tokyo Tower and Yokohama's Bay Bridge were among those to shut off power after Friday's earthquake and ensuing tsunami.

The operators of the Tokyo Tower said the switch-off partially reflected their intention to express their condolences in regard to those who had perished in the disaster.

10.49am: The International Atomic Energy Agency says it was informed by Japanese officials that the explosion at the Fukushima Dai Ichi plant occurred outside the primary containment vessel.

The Tokyo Electric Power Company said the primary containment vessel remains intact, and sea water mixed with boron has been injected into it to limit damage to the reactor core.

However, the explosion resulted in the roof and the walls of the building housing the reactor's container being blown away.

The IAEA said it had been told that four workers were injured at the plant when the explosion occurred.

10.13am: The International Atomic Energy Agency said in a statement today that Japanese officials would distribute iodine to people living near the damaged Fukushima Dai-Ichi nuclear power plant. Iodine can be used to help protect the human body from radiation exposure.

10.07am: In an apparent death hoax, Twitter users informed one another of the death of Pokemon creator Satoshi Tajiri in Friday's disaster. In a tweet, Nintendo of America said none of their Japanese staff were injured during the earthquake. Hello Kitty designer Yuko Yamaguchi was the subject of similar claims.

9.56am: Japan-based tech journalist Martyn Williams has put together a list of Japanese TV news stations being streamed online. They are: NHK (watch) TBS (watch) ANN (watch) NTV (watch)

9.39am: Japan's government broadcaster, NHK, has reported that radiation exposure testing has begun around Fukushima prefecture. Three people randomly selected from a group of 90 tested positive for radiation poisoning.

9.25am: The explosion at the Fukushima Dai-Ichi nuclear power plant after Friday's earthquake and tsunami should prove embarrassing to the Japanese government who were warned long ago about the dangers of building nuclear plants in areas of intense seismic activity, writesGuardian science editor Robin McKie.

9.15am: The Japanese government said radiation emanating after an explosion at the Fukushima Dai-Ichi nuclear power plant, 273km northeast of Tokyo, appeared to have decreased. Officials did not say why, and the precise cause of the explosion and the extent of the ongoing danger remains unclear, reports the Associated Press.

9.04am: Alan Boyle, science editor at msnbc.com, has blogged on the effectiveness of Japan's earthquake warning system and whether the "Big One" could have been predicted days in advance.

8.41am Japan's central bank has promised a "fast response" to the earthquake/tsunami tragedy in the country.

8.40am Japan's Prime Minister Naoto Kan has toured some tsunami-hit areas, by boat - the only practical method of transport in those areas.

8.30am Up to 50,000 search and rescue workers are either already at, or heading to, Japan's worst-hit disaster zones on the north-eastern coast.

8.00am The evacuation zone around the Fukushima No 1 nuclear power plant has now been extended to a 20 kilometre-wide radius. Authorities say the casing surrounding the nuclear reactor has not been damaged - only an external wall has fallen down. So, they say, there is no danger of meltdown occuring.