China on Wednesday asked Deputy Prime Minister Taro Aso to drink treated water that contains radioactive tritium accumulated at the crippled Fukushima No. 1 nuclear power plant, after he said it was safe to drink.

"A Japanese official said it is okay if we drink this water, so then please drink it," Chinese Foreign Ministry spokesman Zhao Lijian told reporters, adding that Japan's "ignorance" of the ecological environment was "totally unjustifiable."

On Tuesday, the Japanese government decided to release the treated water into the sea from the plant in two years, a major development following more than seven years of discussions on how to discharge the water used to cool down melted fuel there.