Ottawa is expanding the size of the Nahanni National Park, adding more than 5,000 square kilometres to the rugged reserve in the southern Northwest Territories, Prime Minister Stephen Harper announced Wednesday.

"This is arguably the most important act of environmental protection in a generation," the prime minister said Wednesday. The government plans to add 5,400 square kilometres of land within the Greater Nahanni ecosystem, barring it from any kind of further development.

(CBC)

That would bring the total area under interim protection for the park — home to spectacular mountains and rivers, grizzly bears, lynx, wolves and other wildlife — up to 28,000 square kilometres. All told, the park now encompasses an area four times the size of Prince Edward Island.

"Canada is blessed with magnificent geography from coast to coast to coast, but none more spectacular than Nahanni Park," Harper said in a statement.

"Today’s announcement will ensure that more of this precious land, and the unique wildlife populations it sustains, will be protected for future generations."

Harper made the announcement in Fort Simpson, N.W.T., kicking off a three-day visit to the North. Environment Minister John Baird accompanied Harper.

The park boundaries will be expanded to include more of the south Nahanni River watershed. 

Nahanni National Park, as seen from the air.
(Donna Lee/CBC)

But Herb Norwegian, grand chief of the Dehcho First Nations, which includes the park area in its territory, was not overly impressed with the announcement. He said governments have talked about expanding the narrow corridor along the river to include the watershed since 1972.

"This has been negotiated and Canada hasn't fulfilled their agreement and that's what this is about. It's catch-up for Canada," he said.

While environmentalists welcome the Nahanni expansion, they have been pushing for inclusion of the entire watershed, which would involve up to 38,000 square kilometres. However, that expansion would also likely include the site of a zinc mine with an ore body worth an estimated $2.5 billion.

Representatives of the Canadian Boreal Initiative and the Canadian Parks and Wilderness Society were to attend Harper's announcement Wednesday.

N.W.T. Premier Joe Handley, lacking confirmation of Harper's visit, left for New Brunswick on Tuesday to join other premiers in meetings of the Council of the Federation.

Reserve is a spectacular site

Known for its spectacular river, deep canyons, huge waterfalls and boreal forest, the Nahanni National Park Reserve attracts adventure visitors to the Northwest Territories every year.

Prime Minister Pierre Trudeau, struck by the area's beauty, established the reserve in 1972 to protect it from proposed hydro-electric development. The United Nations designated it as a world heritage site in 1978.

Discussions on how to expand the reserve's boundaries began shortly after the park was created.

In 2003, the Dehcho First Nations gave Parks Canada temporary protection of an additional 23,000 square kilometres in the area, through an interim land withdrawal process.

The park is roughly 500 kilometres west of Yellowknife.

With files from the Canadian Press