Japan on Wednesday passed a law allowing nuclear reactors to operate beyond 60 years, as it tries to reinvigorate the sector to meet energy challenges and climate targets.

The bill intends to "establish an electricity supply system that will achieve a carbon-free society", a parliament spokesman told AFP.

Those might include changes to safety guidelines, or provisional injunctions by a court.

The new rules allow operators to exclude periods of shutdown when calculating the total years of operation.

However, operators require approval from Japan's nuclear safety watchdog for the exemption, and the law also includes measures intended to strengthen safety checks at ageing reactors.

The government wants to "ensure a stable supply of electricity while promoting the use of carbon-free electricity resources," Japan's ministry of economy, trade and industry said in a statement.

The move comes as Japan's government looks to reinvigorate a nuclear sector that was taken offline after the 2011 Fukushima disaster caused by a deadly tsunami.