Hundreds of Australians turned out Saturday to rally against nuclear power following Japan's Fukushima reactor crisis, at events to commemorate the atomic bombing of Hiroshima during World War II.

Denis Doherty, from Australia's Hiroshima Day Committee, said about 400 people turned out to mark the 66th anniversary of the Hiroshima strike in Sydney and there were similar events at major cities across the nation.

Doherty said the event saw its biggest crowds in several years and had special relevance, given the ongoing nuclear crisis in Japan which was triggered by March's earthquake and tsunami.

"I think people are coming to the realisation that (nuclear) is not the answer to climate change," Doherty told AFP.

"On all sorts of levels I think something is dawning, and if not it should be."

Doherty said the Fukushima incident had rattled the world, evoking memories of Hiroshima with images of "ordinary people" suffering.

"People are starting to think, the cost of 30 years of electricity -- was it worth giving a whole lot of people radiation-induced cancer and destroying large sections of Japanese countryside?" he said.

The massive quake and tsunami on March 11 sent the Fukushima Daiichi facility into meltdown, causing it to leak radiation in the world's worst nuclear accident since the 1985 Chernobyl disaster.

Former Australian diplomat Richard Broinowski said there was a mixture of "anger, indifference, indignation, and some guilt" about the Fukushima crisis in Australia, which is the world's third-largest uranium producer.

"We have anger by the uranium miners who have invested billions of dollars in their projects to mine and export uranium," Broinowski said in a Hiroshima Day speech in Sydney.

"You have guilt on the part of some of these people, not admitted, that the uranium used in the reactors at Fukushima most likely has come from Australia."

Canberra said Australia's uranium production would double in the next four years, despite a Fukushima backlash which has seen Germany abandon nuclear power and Italians vote against resuming an atomic programme.

Japanese Prime Minister Naoto Kan used Hiroshima commemorations to repeat his pledge for a nuclear-free future in his country.