Environmental and funding concerns are adding years to the construction of an Arctic naval port considered crucial to enforcing Canadian control of the Northwest Passage.

The Nanisivik port in Nunavut was originally supposed to be at least partially up and running by next summer, following a promise made by Prime Minister Stephen Harper in 2007.

But no construction is planned for this summer and defence officials admit that the refuelling station, intended to give the navy a permanent presence at the eastern gate of the contested passage, won't be operating for years.

"Construction work at the Nanisivik Naval Facility will begin in 2013," said a defence department spokesman in an email. "It is forecasted that the (facility) will be operational in 2016."

Officials weren't immediately available to explain why. But correspondence with the Nunavut Impact Review Board, which is conducting the project's environmental review, suggests the extra years have been added to the project through a combination of bureaucratic delays, funding problems and environmental liabilities lingering from the site's previous life as a lead-zinc mine.

"There are many challenges operating in the North and DND now has a better understanding of the site condition," wrote the spokesman.

Canadian ships operating in the Arctic are now supplied through ports in Eastern Canada or from supply ships that accompany them. That limits their ability to respond to emergencies.

Nanisivik is intended to allow military vessels to operate with more speed and flexibility as shipping volumes increase in the Northwest Passage. The existence of a working jetty at the former mine site was supposed to speed its construction.

But problems surfaced soon after Harper made his promise.

In 2008, the navy was informed that the project would be subject to an environmental review by the Nunavut Impact Review Board. That board required information on the facility's potential environmental impacts before it would grant a construction.

The navy missed a series of deadlines for information on those impacts.

"I realize that this is taking much longer than expected," said project manager Rodney Watson in a letter to the board in November 2010.

"We were affected by the recession and our design work was put on hold for nearly six months earlier this year due to funding limitations. We were only able to re-start in August 2010."

The navy didn't file its assessment of those impacts until April 29, 2011. Even then, the board found the submission incomplete, listing 16 areas requiring more information.

In addition, the environmental consultants hired by the navy found a series of problems with the site.

In documents posted earlier this month, the consultants reported soil in the area exceeded guidelines for contamination by hydrocarbons and the potentially toxic metals copper, lead, zinc, arsenic and cadmium. Similar problems exist in surface water.

A spokeswoman from Breakwater Resources, the last company to operate the mine, confirms the environmental cleanup is ongoing.

"Reclamation of that facility is under way," said Ann Wilkinson.

Old fuel tanks are being removed this summer. Breakwater is responsible for ensuring its reclamation has been successful and must monitor the site until 2014.

"All our monitoring shows the reclamation has been effective," Wilkinson said.

The delays may have significantly increased the costs of the project.

Although its initial budget was $100 million, Watson told northern media in January the cost of building the facility had grown to $175 million.

Defence officials couldn't confirm that report.

"The overall cost of the Nanisivik project has not yet been fully determined but will be assessed through the design process," the spokesman wrote. "The project cost will likely vary as the project details and options are refined over time."

Still, the delays are unlikely to affect the international debate over whether the Northwest Passage is an internal Canadian waterway, said Whitney Lackenbauer, a historian and Arctic expert at the University of Waterloo.

"I don't see there being an urgent crisis, not do I think this will undermine our international credibility," he said. "We certainly haven't seen the dramatic surge in commercial activity to date that some were projecting."

Recent diplomatic documents released through Wikileaks suggest the U.S. is watching Canada's efforts to enforce its Arctic sovereignty. Some suggest the U.S. doubts Canada's resolve to actually build the military infrastructure it promises.

But Lackenbauer said the military is likely being extra careful with environmental liabilities, given its experience with the lingering toxic residue of Distant Early Warning radar sites left over from the Cold War.

"The military has a very clear sense that it must do due diligence before it gets into any major project in the Arctic," he said. "Every dollar you don't spend up front, you're going to pay many times over at the back end."