Nobel-winning author Kenzaburo Oe said Japan's post-war government and media colluded to give nuclear power a stranglehold, as activists readied for what they hope will be the biggest rally in decades.

The 77-year-old laureate with anti-nuclear views said the media magnate who controlled mass circulation Yomiuri Shimbun had used his newspaper to promote atomic power, in concert with one-time Prime Minister Yasuhiro Nakasone.

"(Nakasone) said because this country does not have resources, Japan would need to find a new source of energy, which the United States had already invented," Oe told reporters in Tokyo.

Nakasone had pushed for nuclear power in the 1950s, and held a number of ministerial posts before becoming prime minister in 1982.

"The United States offered the know-how, the machines and the fuel -- which became the very first bit of nuclear waste now causing a big problem for us -- for free to Japan."

Yomiuri tycoon Matsutaro Shoriki -- who had briefly led the government's science and technology agency -- "jumped at this opportunity" and unquestioningly promoted the technology, Oe said.

"The structure of the Japan in which we now live was set at that time and has continued ever since. It is this that led to the big tragedy" of Fukushima in March 2011, said Oe.

Oe, awarded the 1994 Nobel Prize for Literature and whose novels include "A Quiet Life", was speaking to reporters ahead of what activists say is expected to be one of the biggest demonstrations in Japan of the last two decades.

A series of increasingly large gatherings have been held in Tokyo since the tsunami-sparked disaster at Fukushima, with protestors demanding an end to nuclear power.

The demonstrations have ramped up in the last few months as the issue of nuclear restarts came to prominence, and on Monday, organisers hope 100,000 people will turn up in a park in the west of the capital.

Oscar-winning composer Ryuichi Sakamoto and several other prominent cultural figures, including journalist Satoshi Kamata and economics critic Katsuto Uchihashi have also been involved in the protests.

At the same conference Kamata said Prime Minister Yoshihiko Noda had disregarded the will of the people when he ordered the restart of reactors at the western Oi plant the day after receiving a petition of 7.5 million names.

"It was an extremely insulting gesture," Kamata said.

Uchihashi said Japanese media in general should be more active in covering the demonstrations, including those that have taken place outside the prime minister's office every Friday.

"Before March 11 (last year), all the media played the role of supporting the myth of nuclear safety... It is important for media to be aware of and make known what citizens want in this movement," Kamata added.