Operators of the Fukushima nuclear plant in Japan have begun pumping out thousands of tonnes of highly radioactive water from one of the reactors.

The government says the process is a key step towards restoring cooling systems. The presence of the water has been hindering the work of emergency teams.

About 10,000 tonnes of radioactive water will be transferred from the turbine building of reactor No2 to a treatment facility.

Robots sent inside the reactor buildings have detected high levels of radiation in two cases, and sauna-like conditions in another.

Temperatures of more than 41 degrees and humidity of up to 99 percent steamed up the lenses of the American-built “Packbot” in reactor No2.

The high radiation levels in reactors 1 and 3 confirm the difficulty of the task ahead for workers once they are able to enter.

Officials say the data collected by the robots will not affect plans for stabilising the tsunami-hit complex by the end of the year.

The government says with water being injected there is now no fear of a nuclear meltdown.