Tokyo: Massive amounts of treated but still radioactive water at the tsunami-wrecked Fukushima nuclear plant in Japan could soon start to flow gradually to sea or be allowed to evaporate.

The proposal made by Japan's Economy and Industry Ministry to a body of experts on Monday is the first time the ministry has narrowed down the options available to just releasing the water. It is meant to tackle a huge headache for the plant's operator as storage space runs out, despite fears of a backlash from the public.

An employee walks past storage tanks for contaminated water at the tsunami-crippled Fukushima Dai-ichi nuclear power plant. Credit:Bloomberg/File

Nearly nine years after the 2011 triple meltdowns at Fukushima Dai-ichi, the radioactive water is still accumulating as it is needed to keep the cores cooled and minimise leaks from the damaged reactors.

For years, a government panel has been discussing ways to handle the crisis and to reassure fishermen and residents who fear potential health impacts from releasing it, as well as harm to the region's image.