Canadian Prime Minister Justin Trudeau said Tuesday he would press US President-elect Joe Biden in the coming days to reconsider his decision to scrap the Keystone XL pipeline connecting the Alberta oil sands to coastal refineries in Texas.

Upon taking office Wednesday, Biden is expected to quickly rescind a permit for the pipeline via executive order, effectively blocking completion of the project started almost a decade ago.

"I brought up this issue in my very first conversation with President-elect Biden before Christmas," Trudeau told a news conference.

"Over the past number of days and continuing today, we are communicating our arguments in favor of Keystone XL directly to the highest levels of this (US) administration," he said.

"We're going to continue to make that case, and I look forward to speaking with President Biden in the coming days to talk about this and many other issues that we will work on together as we build back better and as we fight the Covid-19 crisis."

Trudeau acknowledged that Biden had committed to cancelling Keystone XL during his campaign.

The incoming US president told CNBC last May that the pipeline would deliver "tar sands that we don't need, that in fact is a very, very high pollutant."

But Trudeau said "Keystone XL continues to be an important project for us," citing continental energy security, jobs and Canada's efforts to combat climate change.

Canadian regulators approved the project in 2010 but it was then blocked by US president Barack Obama in 2015 due to environmental concerns -- a decision that his successor Donald Trump reversed in 2017.

Owned by TC Energy and the government of Alberta, Keystone XL has been fiercely opposed by environmentalists and indigenous groups because of the risk of oil spills and damage to sites considered sacred.