Uranium from Australia's Ranger Uranium Mine was in the Fukushima nuclear plant on the east coast of Japan when it was hit by a magnitude 9 earthquake, then a 15-metre tsunami on March 11, 2011.

More than 160,000 people had to be evacuated.

For several days after the event - having looked at the damaged Fukushima plant from a helicopter - Mr Kan considered evacuating Japan's largest city, Tokyo, which has 50 million people.

"We were right on the verge," Mr Kan said.

"Within the first 100 hours of the disaster at the Fukushima nuclear power plant, three of the reactors had experienced melt-downs.

"Three of the reactors also experienced hydrogen explosions. If this situation had exacerbated any further we would have been faced with the situation of having to evacuate Tokyo."

Ultimately authorities' ability to use seawater to cool the reactors prevented that happening.

According to the World Nuclear Association, there are still 267,000 tsunami refugees, partly because residents are too nervous of radiation to return to their homes.

A report suggests 5,884 people died in the tsunami and earthquake.

Mr Kan said if he could speak to Queensland Premier Campbell Newman today about uranium exports and nuclear power this is what he would say:

"First of all in Japan, prior to the disaster there were 54 reactors in Japan, however these are all stopped today," Mr Kan told Fairfax Media from Canberra.

"And even if some did restart it would be practically impossible to return to the kind of levels of operation that were in place before the March 2011 disaster.

"Japan will not be consuming anywhere the same levels of uranium it has in the past."

Mr Kan, now a supporter of renewable energy, has been in Australia for the past week on a trip sponsored by the Australian Conservation Foundation during which he is speaking out against uranium mining.

He has told the USA's Huffington Post of his conversion to renewable energy in this way.

"Before the Fukushima accident, with the belief that no nuclear accident would happen as long as the safety measures were followed properly, I had pushed the policy of utilising nuclear power," he wrote.

"Having faced the real accident as prime minister, and having experienced the situation which came so close to requiring me to order the evacuation of 50 million people, my view is now changed 180 degrees."

Mr Kan told Fairfax Media the world market for uranium was simply not as strong as it was before the Fukushima disaster.

"The trends we are seeing in the United States and Europe - and also because of the very high costs of nuclear power - we are not seeing a growth in this market," he said.

"The country with the most plans to expand its nuclear plants is China.

"But China has a very high population density so in the case of any kind of accident it would have a huge impact."

Mr Kan said he would like to see China greatly expand its renewable energy use.

"But at the moment the Chinese government is looking the other way, looking at an increase [in traditional energy]," he said.

Mr Kan said if there was any chance of Queensland developing a uranium market around the world, it would be in China.

He acknowledged Australia – and Queensland - had considerable uranium resources which it had the right to export, with the responsibility for "uranium safety" belonging to the purchasing country.

But Mr Kan said there remained an "ethical responsibility."

"Japan is at the moment looking to export nuclear power plants to India," he said.

"But from my position, I believe that if nuclear power is something we should not be using within Japan, we should not be selling this technology overseas to other countries.

"So from an ethical position I believe this is not correct."

Mr Kan said the long-term health risks from Fukushima's radiation were still being determined, but people did lose their lives very early after the tsunami and the meltdown.

"There were around 60 people who had been in hospital ill, or who were elderly, who lost their lives during the evacuation," he said.

Mr Kan said there has been a major increase in suicides among dairy farmers, who had to kill their cattle herds.

"Thankfully we did not face the situation of such acute exposure to radiation that they lost their lives in the short term," he said.

"However such a large area was suffering this exposure to radiation, that we have to wait to see some of the longer-term effects."

Mr Kan said governments should consider how the use of renewable energy was changing following Fukushima.

"In Japan, in the time since we introduced the [renewables] feed-in tariff, we have seen a 2.5 times increase, particularly in solar and wind production," he said.

"If we are able to continue at this pace, within 10 years we will be able to produce as much electricity through renewable as was produced through nuclear power plants prior to the disaster."

"And I believe this is possible not just in Japan, but in Australia where there is such vast potential for renewable energies."