Japan's industry minister Tuesday rejected a plan by the operator of the crippled Fukushima nuclear plant to release low-level radioactive water into the sea without approval by local fishermen.

"It should not be allowed socially, if not legally, that they forcibly go ahead with the discharge of water without gaining an agreement from fishermen concerned," Yukio Edano, Japan's minister of economy, trade and industry, told a news briefing.

Tokyo Electric Power Co. (TEPCO) said last week that it must release some contaminated water as tanks designed to store it at the plant stricken by Japan's monster quake were expected to hit their limit by next March.

TEPCO added that the waste water -- used to cool Fukushima's nuclear reactors -- would be filtered before it was dumped to reduce the level of radioactivity.

But local fisheries cooperatives and those from other regions have demanded the plan be scrapped amid fears it would further contaminate their fishing grounds and sparked fears among consumers about the safety of their catch.

Edano said Japan's fishing sector had already been dented by "harmful rumours" since the 9.0-magnitude earthquake and tsunami on March 11 knocked out the Fukushima plant's cooling system.

That sparked meltdowns, explosions and the release of huge amounts of radiation into the environment -- the worst nuclear accident since the 1986 Chernobyl disaster.

Thousands of tonnes of water have been pumped into its reactors as TEPCO looks to bring the plant to a cold shutdown by year's end.

Within weeks of the world's worst nuclear crisis since the Chernobyl disaster, TEPCO dumped more than 10,000 tonnes of low-level radioactive water into the Pacific from the plant, located some 220 kilometres (140 miles) northeast of Tokyo.

Subsequent reports have found the radiation was widely dispersed and did not pose a threat to human or animal life.

TEPCO said last week that 150 litres (40 US gallons) of highly radioactive waste water including harmful strontium, a substance linked to bone cancers, was believed to have also found its way into the open ocean from a leaky water-treatment system.

The company said, however, human health should not be affected even after eating sea food caught in the area for every day for one year.