Three entities share responsibility for probing the environmental impact of proposed projects, a system the ruling Liberals say the public does not trust.

Ottawa is due to unveil draft legislation creating a single body to look into projects on federally regulated land, said the sources, who requested anonymity because of the sensitivity of the situation. The announcement could come as early as Tuesday.

"There will be one responsible authority," said one source, adding that the government would stick closely to a plan it issued last June.

Under that plan, the National Energy Board (NEB), which critics say is too close to the industry, would lose the power to assess resource projects.

Prime Minister Justin Trudeau says Canadians need more faith in the assessment system. He also stresses the need for Canada to get landlocked crude to its coasts to fetch better prices.

The industry has become frustrated with the current process, which critics say failed now-canceled pipeline projects such as Enbridge's (>> Enbridge Inc) Northern Gateway and TransCanada's (>> TransCanada Corporation) Energy East.

"We don't want to have a slam dunk-kind process, but the process needs to be fair. It needs to be balanced amongst the various interests," said Chris Bloomer, chief executive of the Canadian Energy Pipeline Association.

"We need to get to clarity, because we're not getting stuff done now."

Green activists and aboriginal protesters, who have had success targeting pipelines, are now focused on Kinder Morgan Canada's (>> Kinder Morgan Canada Ltd) plan to nearly triple the capacity of its Trans Mountain pipeline from Alberta to the Pacific Coast. Trudeau's government approved the expansion in 2016, but it is still facing permit delays.

The legislation could take effect by July 2019, one of the sources said. It would have little immediate impact as projects already under review will continue under the existing system.

While industry has pushed for a two stage review, where it is first determined if a project is in the national interest, green groups are concerned that would undermine subsequent assessments.

"I'm not overly confident we're going to see a strong bill that restores Canadian confidence in the environmental assessment system," said Patrick DeRochie of the Environmental Defence group.

A spokeswoman for Environment Minister Catherine McKenna, who is responsible for pushing the draft legislation through parliament, declined to comment.

$1=$1.24 Canadian

(Reporting by David Ljunggren, additional reporting by Julie Gordon in Vancouver; Editing by Lisa Von Ahn and Susan Thomas)

By David Ljunggren