Naoto Kan, Japan’s Prime Minister, has called on the country gradually to eliminate nuclear power, in his strongest statement on atomic energy since the March tsunami sparked a crisis at the Fukushima Daiichi nuclear plant.

“Our nation should aim to become a society that can manage fine without nuclear power,” Mr. Kan said on Wednesday.

Mr. Kan, who has vowed to step down at an unspecified date, provided few details on timing, but his comments underscore cooling sentiment in Japan toward nuclear power.

In a recent interview with the Financial Times, a leading contender to replace Mr. Kan said Japan should phase out nuclear power over the next two decades. Seiji Maehara, one of the most popular figures in the ruling Democratic party, said construction of new nuclear reactors should “basically be stopped.”

Before the March earthquake and tsunami crippled the Fukushima Daiichi plant, nuclear power accounted for almost a third of electricity generated in Japan. Mr. Kan had previously referred to the technology as continuing to be a “pillar” of energy policy.

Shutting down all Japan’s reactors would have far-reaching implications for the energy sector of the world’s third-largest economy and for nuclear technology companies such as Toshiba, Hitachi and Mitsubishi Heavy Industries.

However, the practical policy implications of Mr. Kan’s call remain unclear, as he is widely seen as a lame duck commanding rapidly declining support even from within his fractious party.

Mr. Kan survived a no-confidence motion in parliament last month only by offering a vague promise to step down when there was a “certain prospect” for progress in dealing with the March disaster and resulting nuclear crisis. Political discussion has been dominated by speculation over how long his administration can last and who might replace him.

Party colleagues and analysts have said Mr. Kan sees adoption of an anti-nuclear policy as a way to rebuild support, but he denied having any plan to dissolve the Diet and fight an election on the issue.

Mr. Kan said the crisis at the Fukushima Daiichi plant, which suffered multiple reactor meltdowns after its back-up cooling systems were knocked out by the tsunami, had shaken his faith in nuclear safety.

The Prime Minister added that resulting mass evacuations and the possibility that it would take decades or more to deal with radiation leakages completely had persuaded him that Japan should reduce its reliance on atomic energy “in a planned and gradual” way.

Support from anti-nuclear activists for Mr. Kan’s call is likely to be muted by his government’s continuing plan to restart reactors currently closed for inspection after they pass new safety checks.

However, public and political support for nuclear power has clearly been weakened by the nuclear crisis, with opinion polls suggesting a majority of voters would like to see either total abolition or reduced use in the future.