A dozen countries with a population of 800 million have agreed on a deal to create the world's largest trade zone.

Canada and 11 other nations are part of the Trans-Pacific Partnership, which covers 40 percent of the world's economy.

The Conservatives have applauded the deal involving Pacific Rim countries, including the United States and Japan. Trade Minister Ed Fast said this morning that the TPP provides Canada a "once-in-a-lifetime opportunity" to gain access to markets in Asia.

"We certainly don't anticipate that there will be job losses," Fast told reporters in Atlanta where the deal was reached.

Liberal Leader Justin Tudeau says his party is "pro-trade" but over the weekend he wouldn't take a position on TPP until the details are released.

NDP Leader Tom Muclair has been more critical, saying his party won't support a trade deal that hurts farming families or auto workers.

Fast, however, claimed that the TPP will not jeopardize Canada's supply-management system because Canada will retain control over the production, price, and importation of dairy products such as milk and cheese.

Signatories to the TPP will reportedly receive duty-free access to 3.25 percent of Canada's dairy production whereas in the past, entire market demand was met by Canadian producers. The federal government has promised a $4.3-billion program over 15 years to help Canadian farmers make the transition.

The agreement needs to be ratified before it takes effect.

In the past, the Vancouver-based nongovernmental organization OpenMedia has criticized the potential impact of the TPP on copyright and intellectual property. The group has claimed that this could jeopardize Internet freedom. 

Meanwhile, the Canadian Centre for Policy Alteratives has warned that the TPP could lead to higher drug prices in Canada.

This came after a leaked draft of the text suggested that pharmaceutical companies would receive longer patent protection, longer periods of data exclusivity, and "stronger patent linkage". According to the CCPA, this would enable brand-name drug manufacturers to delay the approval of cheaper generic drugs by claming that they infringe on existing patents.

Like the North American Free Trade Agreement, the TPP includes an investor-state dispute settlement section. This enables corporations to file complaints against governments and seek compensation from tribunals if they feel they're treated unfairly.