Japan's nuclear watchdog on Wednesday published new draft safety standards that it hopes will prevent a repeat of the disaster at Fukushima.

The Nuclear Regulation Authority (NRA) said measures must be taken to defend atomic power plants against tsunamis, earthquakes and terrorist attacks.

Under the proposed rules there will be a ban on building reactors near active tectonic faults, which themselves will be redefined in a move that will make many more of them fit that definition.

At present, active faults are defined as those that have moved in the last 130,000 years, but the NRA will move the benchmark to any time in the last 400,000 years.

Up to five nuclear plants in Japan sit atop a possible active seismic fault, NRA-appointed experts have said.

Shunichi Tanaka, chairman of the NRA, said earlier this year that plants would have to be able to survive a direct hit from a hijacked airliner or ship, as well as withstand tsunamis like the one that crippled Fukushima.

The move comes after repeated criticism that lax regulation and an overly cosy relationship between authorities and the big-money companies they were supposed to police worsened the catastrophe of March 2011, when a tsunami swamped the coastal Fukushima Daiichi plant.

Hundreds of thousands of people were made homeless by the disaster and tracts of prime agricultural land were left unfarmable after radiation spread across a large area.

Anti-nuclear sentiment is running high in Japan, which used to rely on atomic power for around a third of its electricity needs.

The proposals will now go out to public consultation for 30 days and new rules will come into force in mid-July.

All but two of Japan's reactors remain offline after being shuttered for regular safety checks in the aftermath of the 2011 crisis.