Japan is set to declare that the tsunami-devastated Fukushima Dai-ichi nuclear power plant has finally achieved a “cold shutdown”, meaning it has stabilised and is no longer leaking substantial amounts of radiation.

Traces of radiation from Japan's wrecked nuclear plant have been found in baby formula, the latest case of contaminated food from the disaster.

Experts from the International Atomic Energy Agency have arrived in the Japanese city of Fukushima to observe the massive decontamination effort under way after the world's worst nuclear disaster since Chernobyl.

Up to four people died after a steam leak at a Japanese nuclear plant today.