Denmark has invited Canada, the United States, Norway and Russia to a conference next year to discuss their rival claims to the North Pole.

Danish Foreign Minister Per Stig Moeller said he and Greenland Premier Hans Enoksen have sent invitations this week to the foreign ministers of "all five Arctic superpowers."

Foreign Affairs spokesman Bernard Nguyen said no decision has been made about whether Canada will attend.

"Our position on Arctic sovereignty over our lands and waters is long-standing and based on historic right," Nguyen said.

The five countries are trying to assert sovereignty in the Arctic region, where a U.S. study suggests as much as 25 per cent of the world's undiscovered oil and gas could be hidden.

The race heated up last month when Russia sent two small submarines to plant a tiny national flag under the North Pole in August, and Canada announced plans to build a new army training centre and a deep-water port in the North.

Denmark, the United States and Norway also have claims in the vast region, where the gradual melting of the polar ice could improve access to natural resources and open new shipping lanes.

A Danish tabloid, Jyllands-Posten, said the proposed meeting will be held May 27 to 29 in Ilulissat in Greenland, a semiautonomous territory.

"We've seen different nationalistic manifestations and disputes," Moeller told the Associated Press by telephone.

"We have to discuss ways on how we should behave toward each other and how we should treat the polar region."

Under the 1982 UN Convention on the Law of the Sea, Arctic nations have 10 years after ratification to prove their claims under the largely uncharted polar ice pack.

All but the United States have ratified the treaty.

"We need to find common rules on how we should behave until then," Moeller said. "This is a signal that Denmark and Greenland have thought about the situation."