Google on Thursday began offering the chance for people to wander virtually through an abandoned town deep within the exclusion zone around Japan's crippled nuclear plant.

Visitors to the Internet giant's mapping site can take a tour through the overgrown and deserted streets of Namie, where time appears to have stood still for two years.

Half of the town on the Pacific coast sits within the 20-kilometre (12-mile) evacuation zone around the nuclear plant, which was wrecked when the 2011 tsunami crashed into Japan.

With cooling systems knocked out by the tsunami, three reactors at the plant melted down, spewing radioactive particles into the air, soil and sea and forcing Namie's entire population of 21,000 to flee.

"The world is moving on to the future after the disaster... but time has stopped in the town of Namie," said mayor Tamotsu Baba, writing on a blog for Google Japan.

"I hope these street views will show the people of future generations what the great earthquake and nuclear disaster brought," he said.

"We need many years and many people's cooperation to rise again from the nuclear crisis. We will never give up on getting back our hometown," he said.

The natural disasters killed nearly 19,000 people, including those whose bodies are yet to be recovered.

Some parts of the town were swamped by the waves of March 11. Houses and other buildings damaged by the water can be clearly seen.

But many of the buildings are intact, abandoned when the sudden order to evacuate came two years ago.

Tens of thousands of people in the area were forced from their homes by the nuclear catastrophe, the worst the world has seen since the 1986 disaster at Chernobyl.

No one is officially recorded as having died as a direct result of the radiation, but scientists warn some areas may remain contaminated for decades, while those most heavily polluted could be uninhabitable forever.

The map can be found here: