The Dutch government has asked the International Tribunal for the Law of the Sea to order Russia to release 30 people detained last month during an environmental protest in the Arctic Sea.

The 30 crew members of Greenpeace's Arctic Sunrise had been charged with piracy after protesting Arctic oil drilling.

"The (Dutch) state is asking for the freeing of the detained crew and the release of the Greenpeace ship," before the German-based International Tribunal for the Law of the Sea, a statement said on Monday.

"Because the Netherlands find that the ship's release and the freeing of the crew is an urgent matter, it has now decided on this step," it added.

Russian authorities have charged the environmental group's crew members with piracy, which carries a 15-year sentence, after they staged a protest against Arctic oil drilling last month.

The activists from 18 different countries have been placed in pre-trial detention until late November in the northern Russian city of Murmansk.

Last week, a Murmansk court rejected several bail requests, ignoring a worldwide campaign to have the piracy charges dropped.

The Dutch government said it expected a hearing within the next two to three weeks before the Hamburg-based tribunal.