Up to 1,000 bodies are thought to be in the area, but their retrieval has been delayed because of radiation fears.

Staff are working to bring the nuclear plant under control, after cooling systems at three reactors were knocked out by the quake.

More than 300 police in protective gear are searching for bodies.

It is the first time an operation to find those killed by the earthquake and tsunami has been carried out in the 10km (six-mile) zone around the plant.

Police said falling radiation levels had made it possible.

"The search started around 1000 and will continue until sunset," a police spokesman said. "It's difficult to estimate how many people are still missing in the area. We have to go and find them as soon as possible.

"If we find bodies contaminated with high levels of radiation, we will wash the remains before we take them to a morgue."

The earthquake left 13,456 people dead and another 14,851 missing. More than 150,000 have been made homeless.