Japanese Prime Minister Yoshihiko Noda is expected to announce on Friday that the crippled Fukushima nuclear plant has been brought under control, reports said.

Noda will hold a press conference Friday from 6:00 pm (0900 GMT), with local media saying he will proclaim cold shutdown of the plant.

The announcement would be in line with the Japanese government's promise of achieving cold shutdown of the overheating reactors by the year's end.

The announcement will be followed by fresh steps toward decommissioning the reactors, a process that is expected to take more than three decades.

The Fukushima Daiichi nuclear plant was severely damaged by a 9.0-magnitude earthquake and resulting tsunami on March 11, which knocked out cooling systems.

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

The plant's operator Tokyo Electric Power has poured water into the reactors to cool the melted fuel rods inside.

The utility has faced a number of technical problems as it worked to process tonnes of radioactive water generated by this cooling, but the operation has stablised in recent months.

The nuclear disaster prompted fears of radiation contamination across eastern Japan, with many consumers trying to avoid fish and farm products from the region.