Norway's Parliament has opened up a new area on the fringe of the Arctic Ocean to offshore oil drilling despite protests from opponents who fear catastrophic oil spills in the remote and icy region.

Most of the Norwegian sector of the Barents Sea, which the Nordic country shares with Russia, is already open to petroleum activities.

But environmentalists and some opposition lawmakers say the risk to Arctic sea ice is higher in a Switzerland-sized area straddling the Russian maritime border, and wanted to make parts of it off limits to oil and gas drilling.

Parliament sided with the government in a vote late Wednesday and opened the entire area to drilling, with the caveat that no activity can take place within 31 miles (50 kilometers) of the ice edge.

"This is a clear break in Norwegian policy," said Nils Harley Boisen, of the World Wildlife Fund. "And moving completely against all expert advice on what is safe operations."

In 2003, Arctic sea ice extended into the northern part of that area, he said.

Christian Democrat lawmaker Kjell Ingolf Ropstad, who opposed the move, said operations in icy waters are complicated, risky and potentially hazardous to sensitive Arctic ecosystems.

The government says the environmental risks will be managed carefully, noting that Norway doesn't allow drilling in areas covered by sea ice.

Norway has become one of the world's richest countries per capita thanks to exports from its offshore oil and gas industry. It's now moving its search into the Arctic region in a bid to offset declining production in the North Sea.

The slice of the Barents Sea that was opened by Parliament on Wednesday is in an area that was disputed with Russia until the countries signed a maritime border deal in 2010.

Ben Ayliffe, an Arctic campaigner at Greenpeace, said the move highlights the oil industry's creep toward the North Pole as climate change thaws the frozen region — estimated to hold up to 13 percent of the world's undiscovered oil and 30 percent of its untapped natural gas.

However, he added that the Arctic oil rush seems to have lost steam with Shell cancelling drilling plans off Alaska this year, Conoco-Phillips suspending plans for Arctic drilling in 2014 and Statoil postponing plans to drill its northernmost well ever in the Barents Sea partly because it couldn't get a rig "winterized" in time.