Denmark's prime minister rejected Tuesday calls to block a Greenland law that will allow foreign mining companies to employ workers under conditions prevalent in their own countries.

"I believe that we must have respect for the home rule that we have agreed, and that we respect the decisions taken in Greenland," Helle Thorning-Schmidt told reporters.

The prime minister's statements came following political and union criticism of Greenland's new law, which is predominantly seen as favouring China's plans for a large-scale mining settlement on the world's largest island.

Greenland's parliament last Friday passed a law that gives companies investing in large-scale mining operations in the country free rein to determine their own employee working conditions.

Under commonwealth rules, however, the law must be sanctioned by Denmark's Parliament.

Greenland is part of the Danish commonwealth and while it has full control over its raw materials, foreign policy and defence matters remain under Copenhagen's control.

"We have to accept that raw materials, wages and employment are conditions that are decided in Greenland. It is not up to me or any other politician (in Denmark) to decide what they do in Greenland," Thorning-Schmidt said.

However Danish People's Party leader Kristian Thulesen Dahl has warned he would try to raise a parliamentary majority to block the law coming into effect, saying immigration policy remained a commonwealth responsibility.