Japan will go without nuclear power for a period starting September when its only two operating reactors are shut down for mandatory safety checks, a utility company said Wednesday.

Kansai Electric Power, which runs both reactors at the Oi nuclear plant in western Japan, said the units will go offline on September 2 and 15 respectively for an indefinite duration.

The country's 50 nuclear reactors were shuttered after an earthquake and tsunami in March 2011 caused meltdowns at the Fukushima nuclear plant in northeast Japan, fuelling widespread public opposition to a once-trusted technology.

The two Oi reactors resumed operation in July last year while two other units at the same plant have remained offline for safety checks.

Japanese power companies last month asked for permission to restart 10 nuclear reactors, a move that could presage a return to atomic energy more than two years after the Fukushima disaster.

The firms submitted applications to regulators for safety assessments on units at five separate plants on the day that new beefed-up rules came into force.

The requests are the first step on a journey that could take many months, but which commentators say is likely to result in the resumption of nuclear power generation in Japan.

The crisis at Fukushima was the worst nuclear accident since Chernobyl in 1986.

A vocal anti-atomic campaign, whose leading lights say the industry had an overly cosy relationship with its regulators in the decades leading up to the disaster, nudged the government into establishing a new industry watchdog.

It has set stricter standards that operators must show they can meet before they will be granted permission to re-start idle reactors.