It will take at least 10 years before any work starts on a proposed Alaska Highway gas pipeline through the Yukon, a gas company executive says.

Ron Brintnell, director of gas development at Enbridge Inc., told delegates Tuesday at the Resource Development and Northern Transportation Conference in Whitehorse that the proposed project is at least a decade away and the cost of it would be anyone's guess.

"There's never been an infrastructure project of this magnitude in North America. It could quite possibly [be] the largest private-sector construction project in the world," he said.

"When can you expect to see Alaska Gas? We don't know; 2020-plus is not unrealistic…. It depends on how the process goes."

Enbridge is one of several companies that hopes to build the proposed 2,810-kilometre pipeline that would transport gas from Alaska's North Slope through the Yukon and northern B.C. to Alberta.

But Brintnell said he anticipates several expensive hurdles: for starters, he estimated Enbridge will spend at least $1 billion to move the proposal through the regulatory process.

"Think about that: a billion dollars just to get through the regulatory process. Most projects don't cost a billion dollars," he said.

He also cited rising steel and other construction-related costs, and said the 132-centimetre pipe Enbridge wants to use has never been built.

"No one really knows what this pipeline project will cost. There hasn't been an update for the Alaskan line for a long time," Brintnell said, adding that the last major estimate was made in 2001.

"We think that just the A to B portion could be well in excess of $20 billion. If that's Canadian dollars or U.S. dollars, we're still talking about a lot of money."

Brintnell also raised major concerns about skilled labour, as he said Canada does not have the qualified workers to build a pipeline.

He said the state of Alaska will be calling for proposals for the proposed project before the end of this summer.