Canada has been invited to join trade talks with the world's Asia-Pacific countries, Prime Minister Stephen Harper says.

Months after Canada started pursuing entry into the talks, and years after it eschewed them in favour of focusing on Canada-EU talks, the countries negotiating the Trans-Pacific Partnership have invited Canada to join them at the table.

"This is a further example of our determination to diversify our exports and to create jobs, growth and long-term prosperity for Canadian families," Harper said from Mexico on Tuesday.

Canada becomes the 11th country to get involved. Mexico was invited in Monday, joining Australia, Brunei, Chile, Malaysia, New Zealand, Peru, Singapore, the United States and Vietnam.

With Canada and Mexico entering the talks, the countries involved represent 658 million people and a gross domestic product of $20.5 trillion, according to a release from the Prime Minister's Office.

Many believe the deal will have more economic strength than the North American Free Trade Agreement.

Harper said that Canada hasn't agreed to any specific measures in terms of an eventual Trans-Pacific Partnership agreement. But as a latecomer, Canada has had to accept without question all that has already been agreed to by the TPP partners.

"There is an accession process, so we don't disrupt the negotiations," Harper said. "We're obviously not going to try to undo what's been done, but these negotiations in our judgment are at fairly preliminary phases right now."

"As in any negotiation, nothing is agreed to until everything is agreed to by all parties," said Harper, who stayed vague about the terms of Canada's entry into the TPP talks.

Market access for dairy products has been a contentious issue in the TPP negotiations so far, particularly for the United States and New Zealand. Some speculated that Canada's trade restrictions on dairy and poultry products were holding it back from joining the talks earlier.

Canada has a supply management system that controls domestic milk and egg prices while setting prohibitively high tariffs on imports. Despite pressure from business and consumer groups to ease up on the controls, the Harper government (as well as all three opposition parties) have steadfastly defended the system.

"As the prime minister said, everything that we would sign for the future would have to be for the benefit of Canada," Industry Minister Christian Paradis told reporters before question period in the House of Commons on Tuesday.

"We always said that we stand by supply management," added the Quebec minister.

"We did not give away anything to get to the table," Gerald Keddy, the parliamentary secretary to the trade minister, said during question period.

1st meeting likely not until fall

Another anticipated announcement about Canada's first steps toward closer trade ties with China was postponed due to diplomatic roadblocks.

The federal government is also pursuing trade deals with India and has launched negotiations with Japan.

Canada's admission into the free-trade deal must be approved by all the other countries.

The government first announced an interest in joining the TPP talks last November. It will take several months to ratify Canada's participation, with the next chance to join the talks early this fall, although the negotiations will go ahead first without Canada in July.

"One of the things that happens on an administrative level is the U.S. government gives 90 days notice to Congress, before it starts negotiating with anybody," Laura Dawson, a specialist in international trade agreements, told CBC's Carol Off.

"So even though there's no longer blockages from the other members, our actual participation in the negotiations will be at least 90 days, if not more."

By the time Canada joins the United States, Australia, New Zealand, Peru, Chile, Singapore, Malaysia, Vietnam and Brunei at the table — with Mexico also coming in late — 12 rounds of negotiations will have already taken place since 2010, The Canadian Press reported.

The government has not released a cost-benefit study to speculate how much could be gained and at what possible price, as it did during past negotiations with Europe and India.

Earlier this year, Canada launched negotiations toward a free trade agreement with Japan, which will generate billions of dollars in commercial flows between the two countries. Canada also announced formal exploratory talks toward a potential free trade agreement with Thailand, Canada’s largest bilateral trade partner in Southeast Asia.

Harper made the announcement at a meeting with U.S. President Barack Obama as the G20 summit in Mexico came to a close.

With files from Louise Elliott, Janyce McGregor, Terry Milewski and The Canadian Press