TOKYO • Japan's Kyushu Electric Power is monitoring activity at a volcano near its Sendai nuclear plant and says it does not need to take special precautions after the authorities warned of the risk of a larger-than-usual eruption.

The reactor is the first to be restarted under new safety standards put in place since the meltdowns at Fukushima in 2011. Prime Minister Shinzo Abe and much of Japanese industry want reactors to be switched on again to cut fuel bills, but opinion polls show a majority of the public opposes the move after the nuclear crisis triggered by an earthquake and tsunami.

The possibility of a significant eruption of Sakurajima, about 50km from Sendai, is a reminder of the volatile geology of Japan, which has 110 active volcanoes.

"We are not currently taking any particular response," Kyushu Electric spokesman Tomomitsu Sakata said yesterday. "There is no impact in particular on the operations" of the Sendai plant, he said. "We will continue to pay close attention to information from the Japan Meteorological Agency."

The 890MW reactor, restarted only this month, had reached 50 per cent of its output by Sunday and the operator expects full power to be achieved around Aug 24, Mr Sakata said.

Critics of the nuclear industry say new safety measures are insufficient, particularly for plants such as Sendai, which is located near five giant calderas or crater-like depressions formed by past eruptions, with the closest one about 40km away.

Sakurajima is one of Japan's most active volcanoes and erupts almost constantly. There was a risk of larger-than-usual eruption, an official at the Japan Meteorological Agency said last Saturday.

The agency raised the warning level on the peak, about 1,000km south-west of Tokyo, to an unprecedented 4 - prepare to evacuate - from 3. REUTERS