Gusty winds prevented the operator of the crippled Fukushima No. 1 nuclear plant from starting to dismantle treated water tanks on Thursday, a crucial step towards decommissioning the entire facility.

The "water tank dismantling has been postponed because of strong winds," Tatsuya Matoba, a Tokyo Electric Power Company (Tepco) spokesperson, said.

"The process could start from tomorrow depending on weather conditions," he added.

The dismantling had been seen as a milestone in Tepco's decades-long project to decommission the stricken plant in northern Japan, which went into meltdown after it was hit by a catastrophic tsunami in 2011.

Officials were to have started the process on Thursday to get rid of some of the tanks to clear space needed to store nuclear debris to be extracted from the plant's reactors.

Tepco has stored around 1.3 million tons of water — a combination of groundwater, seawater and rainwater — at the site, along with water used for cooling the reactors, since the 2011 accident.

The water has been filtered to remove various radioactive materials but remains inside more than 1,000 tanks that occupy much of the plant site.

Scrapping the water tanks became possible after Tepco began releasing the stored water from the plant into the Pacific Ocean in August 2023.

After removing the tanks, the utility plans to build facilities to store highly dangerous molten fuel debris to be extricated from inside the reactors.