Conservative Leader Stephen Harper warned the Canadian auto industry it may not be happy with elements of a proposed Pacific trade pact during Thursday's Globe and Mail leaders' debate.

Unifor and some Canadian auto parts makers are leery about proposed elements of the Trans-Pacific Partnership that would allow Japanese companies export cars to North America with substantially less North American content than currently required.

Canada and Mexico, both home to major auto parts and assembly plants, are angry that the United States wants to let Japan export cars to North America with substantial content from non-TPP nations. This, they fear, could make Canadian and Mexican autos too expensive.

Harper said securing Canadian access to fast-growing Asian markets was the most important part of the deal.

"What I say to the auto sector in particular — I am not suggesting they will like everything that is in that — is we simply cannot afford as a country to have our auto sector shut out of global supply chains," Harper said.

"That would be a disaster. We're going to make sure we get the best deal for that and all of our sectors," he said.

He did not give specifics as to what concessions the automotive industry would need to make.

Negotiations to finalize the deal failed in late July, but representatives from the United States, Canada, Mexico and Japan are scheduled to meet next week to discuss the automotive sector ahead of further negotiations in late September.

"Nothing's concluded until it's all concluded, but I believe there will be a deal at some point," Harper told reporters Friday in Calgary. "We will obviously work to advance the interest and protect all of our sectors, but I think it is vitally important that should such a deal arrive, arise, that Canada be part of the future trading network of the Asia-Pacific region."

Earlier in the week, U.S. President Barack Obama said he was confident a deal could be finalised this year.