TOKYO -­ Prime Minister Stephen Harper is billing the official launch of free trade talks between Canada and Japan as "historic."

The potential deal, announced by Harper and Japanese Prime Minister Yoshihiko Noda in Tokyo on Sunday, could increase Canada's exports to Japan by some two-thirds.

The Conservative government has been courting Japan since the idea of a trade deal was floated in 2007.

But it has been an uphill battle for Canada, which has more to gain from a free trade agreement.

"They certainly have been reluctant to engage in the kind of negotiations we've now committed to engage in," Harper conceded.

"So getting an agreement to move forward on free trade discussions is a major step forward."

While Harper cheered the launch of the talks during his official visit to this country, he's likely to face a backlash from Canada's auto lobby when he returns to Ottawa.

The Canadian Auto Workers union has long opposed a free trade deal with Japan, arguing it would deal a blow to the sector.

Harper said Canadian negotiators would fight to protect Canadian interests at the bargaining table - but hinted the deal wouldn't rest on the fate of any one industry.

"In the end we have to do what's best for the entire Canadian economy," he told reporters.

Travis Toews, formerly with the Canadian Cattlemen's Association, said he's excited about the new talks and sees a future benefit for Canada's agriculture and beef industries - but knows there'll be some give and take.

"We know Japan will have ambitions for Canada and we believe trade should be a two-way street," he said.

Bilateral merchandise trade in 2011 stood at $23.7 billion.

But a recent Canada-Japan study into an economic partnership indicated a deal could boost Canada's GDP from between $3.8 billion and $9 billion - an increase of between 0.24% and 0.57%.

Japan's GDP could only see a minimal 0.09% bump.

Starting trade talks are an early step in what can be a drawn out process.

Canada is in the midst trade negotiations with 52 countries - including those in the European Union. Some talks - like those with South Korea - have been dragging on for years.

The prime minister is on a six-day tour of Asia, with stops in Thailand, Japan and South Korea.