A group of prominent activists is calling for a sit-in to take place in Ottawa to protest Alberta's oilsands.

The civil disobedience is inspired by action in Washington, D.C., this week in which Canadian actress Margot Kidder and dozens of others were arrested.

The Council of Canadians, Indigenous Environmental Network and Greenpeace Canada hope to make the event "one of the largest acts of civil disobedience on the climate issue that Canada has ever seen," they say on the website set up to promote the event.

The Washington protesters are trying to convince the U.S. government not to approve TransCanada Corp.'s Keystone XL pipeline project, which would transport crude oil from Alberta to U.S. markets in Illinois and Oklahoma. The Keystone XL would be an extension of the existing line to Houston, TX.

The Canadian protest is set for Sept. 26, but there are no further details on what it will entail. The website warns participants will be risking arrest.

Maude Barlow, chair of the Council of Canadians, says the government needs a conversion plan to move to alternate energy sources.

"Tar sands mining has destroyed much of Alberta's water table and will put the fragile Ogallala Aquifer [the world's largest known aquifer] in peril. We join with the millions of Americans who oppose the expansion of this deadly industry," she said in a statement.

Alykhan Velshi, who runs a blog called ethicaloil.org that aims to promote Canadian oil, says the oilsands industry is improving, cutting carbon emissions and moving away from open pit mining. He says much of the oil around the world comes from countries with poor human rights records, so buying oil from Canadian companies is at least less money going to those countries.

"Obviously, groups like environmental organizations are free within our law to protest the oilsands. Certainly Canada is a country with free speech and they're exercising free speech," he said.

"I consider it unfortunate they're attacking Canada — a liberal democracy — and directing so few of their energies on Saudi Arabia and Venezuela.... I think their priorities are misplaced."

The U.S. State Department's environmental assessment on Keystone is due Friday.