A free trade deal with Japan could boost Canada's trade output by 60 per cent and open up the country's tightly controlled agricultural market, Prime Minister Stephen Harper says.

Harper called the opening of free trade talks with Tokyo an "historic opportunity" to access the world's third-largest economy.

But experts warn no other member of the so-called Group of Eight has a free trade deal with Japan.

Ron MacIntosh said the Harper government will endure a learning curve in "Asian realities." He's a research associate at China Institute and former trade negotiator who served in Japan, South Korea and Taiwan.

Canadians will have to remind themselves that free trade in this part of the world is about more than just lowering tariffs and distorting subsidies, MacIntosh said.

It also includes investment rules, intellectual property, competition policy and currency management, among other things, he said.

Harper said any deal would be good for the Canadian economy and promised "various" sectors would be protected.

But that might be a challenge.

The Japanese are skilled and formidable negotiators. Experts say they need a deal that works to their advantage because their economy is stagnant while the giant beside them, China, is booming.

"We are dealing in East Asia with sophisticated states with strong negotiating teams, and often with strong domestic lobbies," said Gordon Houlden, a trade expert and former government official.

Houlden warned a quick agreement isn't likely and predicted that one of Canada's main objectives -- gaining greater access to the Japanese agriculture market -- will face stiff opposition.

"Agriculture in Japan is super-protected and has an almost mystical status," said Houlden. Australia struggled with similar issues in its negotiations with Tokyo, he noted.

Harper, however, is optimistic a free trade deal with the Asian economic powerhouse would benefit Canadian exports.

"The potential for increased trade between us that will create jobs and growth and long-term prosperity is really enormous," Harper said following talks with Japanese Prime Minister Yoshihiko Noda.

Noda told a joint news conference that Japan was interested in increasing investment in Canada's natural gas sector.

Japan is looking at divesting its nuclear power reliance after the tsunami disaster caused a meltdown at its Fukushima reactor.

Noda also announced the two countries will pursue enhanced defence and security co-operation, including the establishment of a small supply base the Canadian military could use in emergencies.

That's not a surprising move since the threat of North Korea's nuclear and missile programs looms on its borders. Japan has threatened to shoot down a long-range missile North Korea has said it will launch next month.

"We reaffirmed the importance to tackle outstanding global issues, particularly the issues surrounding North Korea and others in the Asia-Pacific region, as we co-operate as partners," Noda said.

Japanese and Canadian leaders will be heading to Seoul to attend this week's Nuclear Security Summit.

Harper will also visit the earthquake and tsunami-ravaged region of Sendai on Monday and made a point of praising Noda for "the true and clear leadership" he showed through the crisis, and how quickly Japan has rebuilt.

"I have quite great admiration for what you are doing here," he said.