The claim, which was to be filed with the United Nations in New York on Monday, will force Canada into tough future negotiations on overlapping claims instead of being able to rely on deals worked out in advance, said University of British Columbia international law professor Michael Byers.
"Most people who follow this issue are wishing that we hadn't arrived at this point, that the gentleman's agreement was going to take care of these matters and set in place a workable agreement that would have provided stability," Byers said from Novosibirsk, Russia.
Rob Huebert at the University of Calgary's Centre for Military and Strategic Studies said any such agreement was doomed from the start.
"I think we got sold a bill of goods," he said. "I don't think the Russians or the Danes, once it came up to the political leadership, ever really intended to do that."
Interest in the Arctic is intensifying as global warming shrinks the polar ice and opens up possible resource development, potential new fisheries and new shipping lanes.
The area is believed to hold an estimated 13 per cent of the world's undiscovered oil and 30 per cent of its untapped gas.
Danish Foreign Minister Martin Lidegaard says scientific data shows Greenland's continental shelf is connected to the 2,000-kilometre-long Lomonosov Ridge beneath the Arctic Ocean. He says that gives Danes a claim to the North Pole and any resources on the sea floor.
The United Nations panel is to eventually decide control of the area. The Danes claim the right to exploit an area of 895,000 square kilometres. The area goes right up to Russia's exclusive economic zone 370 kilometres off its shoreline.
Last December, Canada surprised its Arctic neighbours when it made its own filing under the United Nations Convention on Law of the Sea. It said the Arctic component, which had been widely expected to stop just short of the North Pole, wasn't complete and that it would eventually include data backing up a claim that would include the Pole and waters beyond.
Documents obtained The Canadian Press suggest that announcement also surprised Canadian government officials. Foreign Affairs Minister John Baird has not disputed published reports that Prime Minister Stephen Harper stepped in at the last minute to insist that the North Pole be included in the claim.
Huebert said Denmark's move wasn't a surprise.
"This is the process. We shouldn't be surprised at them going for the maximum that they can."
Actual boundaries on the sea floor are to be settled by international negotiations. Those talks won't begin until scientific data filed by the contesting nations is examined. That is expected to take 10 to 15 years.
By then, however, climate change will have gone even further. That could make Arctic resources from energy to fisheries more accessible — and more contentious.
"It's generally a good thing to negotiate issues when the stakes are relatively small," said Byers. "Once the stakes grow, then you get vested interests and more political possibilities."
Huebert said the temperature of the talks will depend on the geopolitics of the time.
"It's going to be like it is everywhere else. If this was any other ocean space in the world, no one would be saying, 'We'll have an artificial point that automatically gives us less.'"
Russia has previously filed a submission for the sea floor up to the North Pole, but is expected to file a revised version in the spring. Foreign Minister Sergei Lavrov said in September that claim will form a triangle with its apex at the North Pole.
"It's entirely possible that Russia will expand its forthcoming submission to include seabed all the way up to Denmark and Canada's exclusive economic zone," said Byers.
"They're perfectly entitled to do that, but it would be the international law equivalent of flying a Tupolev bomber to 201 nautical miles from the Canadian coast. It's still not considered an entirely friendly action."
Canadian government spokesman John Babcock said Denmark's move was not unexpected.
"Canada, Denmark, Russia and the U.S. are all expected to be able to define large continental shelves in the Arctic Ocean," he said in an emailed statement. Canada and Denmark continue to enjoy a positive relationship, Babcock said.
"The government’s objective has been to obtain the most expansive continental shelf for Canada."
— With files from The Associated Press