Very high levels of radiation detected in water leaking from a reactor at a nuclear plant in Japan dealt a new setback on March 27 to efforts to bring the stricken facility under control.

The operator of the Fukushima Daiichi plant said it had detected radiation levels 10 million times higher than usual in leaked water at reactor two, as white steam continued to rise from the tsunami-battered facility, AFP reported.

The radiation level was 1,000 millisieverts per hour, making it too dangerous to remain at the reactor turbine building and forcing the evacuation of workers there, plant operator Tokyo Electric Power said, according to au.news.yahoo.com.

"It is an extremely high figure," nuclear safety agency spokesman Hidehiko Nishiyama said of the latest reading. "There is a high possibility that (the water) came from the reactor."