Google has rolled out a detailed map of North Korea that even labels some of its remote and infamous gulags.

Until now North Korea was pretty much a blank canvas to users of Google's Map Maker, which creates maps from data that is provided by the public and fact-checked in a similar process to that used by Wikipedia.

"For a long time, one of the largest places with limited map data has been North Korea, but today we are changing that," said Jayanth Mysore, a senior product manager at Google Map Maker.

Mr Mysore said the North Korea section had been completed with the help of a "community of citizen cartographers" working over a period of several years.

"While many people around the globe are fascinated with North Korea, these maps are especially important for the citizens of South Korea, who have ancestral connections or still have family living there," he said.

With the two countries still technically at war, decent maps of the North are almost impossible to come by in South Korea.

Ironically, the people least able to benefit from the Google publication are the North Koreans themselves, who live in one of the world's most isolated and highly censored societies.

The North has a domestic intranet but it is cut off from the rest of the world, allowing its very limited number of users to exchange state-approved information and little more.

Access to the world-wide web is for the super-elite only, meaning a few hundred people or maybe 1,000 at most, experts estimate.

The Google version offers a detailed map of the capital Pyongyang, showing hospitals, subway stops and schools.

Outside the capital, the detail is sketchier, but noticeable on an overview of the country are a series of city-sized, grey-coloured areas which, when zoomed in on, are identified as sprawling re-education camps.

As many as 200,000 people are estimated to be detained in the vast gulag system, many under a guilt-by-association system that punishes those related to someone perceived as an enemy of the state.

The release of Google's new North Korea map came just weeks after its chairman Eric Schmidt returned from a controversial trip to Pyongyang as part of a US "humanitarian" mission.

On his return, Mr Schmidt said he had told officials in the North that the country would never develop unless it embraced internet freedom.