OTTAWA - CTV News has learned that the federal government is about to protect thousands of square kilometres in Canada's Far North from any mining or oil and gas development, a move that could help Prime Minister Stephen Harper's government burnish its green credentials.

Some native and conservation groups have been pushing for a moratorium on industrial development in all 39,000 square kilometres of the South Nahanni watershed in the Northwest Territories.

Right now, 23,000 square kilometres of land, including the Nahanni National Park Reserve of Canada, is under protection.

Tomorrow, Environment Minister John Baird will be in the Northwest Territories to announce the protection will be extended to thousands more square kilometres in the watershed.

Sources tell CTV News they expect Baird to set aside between 4,000 to 5,000 additional square kilometres.

"What we expect is a significant next step but not the brass ring," said Larry Innes, the executive director of conservation group, Canadian Boreal Initiative.

Harper is travelling in Canada's Far North this week and will also be in Fort Simpson, NWT tomorrow although it's not yet clear if he will join Baird for the announcement.

The Nahanni National Park Reserve of Canada is a national icon and has been designated as a World Heritage Site by the United Nations.