The pact, known as the Trans-Pacific Partnership (TPP), has faced stumbling blocks, in significant part because of wrangling between its two biggest economies, the United States and Japan, over agricultural tariffs.
Progress on the talks has been held up largely on Japan's insistence on protecting politically powerful farm sectors such as beef.
Some U.S. lawmakers have been pushing to include rules against currency manipulation in trade agreements. However, speaking on condition of anonymity, another Mexican official familiar with the TPP negotiations said it looked too late to include such a measure.
Potentially one of the world's biggest trade pacts, the TPP would link up a dozen Asia-Pacific economies by eliminating trade barriers and harmonizing regulations in a pact covering two-fifths of the world economy and a third of all global trade.
Tokyo and Washington have stressed the trade pact would have strategic implications as well, creating a framework for business that could entice China to play by global rules.