The head of the Japanese fisheries federation has reiterated his firm opposition to the government's plan to release into the sea treated water from the Fukushima Daiichi nuclear power plant.

Water used to cool molten nuclear fuel at the plant, mixed with groundwater and rainwater, is treated to remove most radioactive materials.

The government plans to dilute the treated water containing tritium and other radioactive substances to levels below national limits and start discharging it into the ocean around next spring.

On Tuesday, industry minister Hagiuda Koichi met Kishi Hiroshi, president of the National Federation of Fisheries Cooperative Associations, in Tokyo.

Hagiuda said the government will set up a fund to offset possible reputational damage after the water is discharged. He also pledged long-term support to ensure that fishers can keep doing business without worry.

But Kishi said there's no change in the federation's firm opposition to water discharge that lacks the support of the public and fishers nationwide.

Kishi later told reporters that it's been a year since the government decided on the plan, but that the two sides remain far apart.

He noted that some countries still ban imports of Japanese seafood, and urged the government to do more to address the issue of reputational damage.