The United States and Mexico appear to have taken the first steps toward renegotiating the North American Free Trade Agreement, according to a Mexican government documents, walking down a path that would fulfil one of President Donald Trump's big campaign promises and potentially transform the hemisphere's economy.

A communique posted by Mexico's foreign and economic ministries on a government website on Thursday (AEDT) said that the Mexican government had begun a series of consultations with the private sector, a process which it said would take 90 days. "The consultation in Mexico will start simultaneously with the internal process being carried out by the government of the United States," the document said.

The White House did not respond to a request for comment and officials in the US Congress said they had not yet been notified of any formal action. But trade economists said the process might be tied to US legislation passed under former president Barack Obama that gives the president power to quickly broker a new trade agreement. Called fast-track authority, it requires the president to notify Congress 90 days before signing a new trade agreement.

If the White House is indeed proceeding under fast-track authority, that suggests Trump could intend to scrap NAFTA altogether and forge bilateral trade deals with Mexico and Canada instead, said Gary Hufbauer, a senior fellow at the Peterson Institute for International Economics. Trump and his administration have expressed a preference for bilateral deals, which they say allow the US to better wield its economic heft at the negotiating table.

"I think they want to retire the name NAFTA, say they got rid of it, then put it into the history books," said Hufbauer.

It's still possible, however, that the process will be terminated if the US, Mexico and Canada agree to terms overhauling NAFTA.

Renegotiating NAFTA was one of the major promises Trump made on the campaign trail, where he criticised the 25-year-old trade pact for hollowing out America's manufacturing sector. The news comes as Trump reassesses America's system of trade and immigration. He has already pulled out of the Trans-Pacific Partnership, a Pacific Rim trade deal crafted by the Obama administration.

This historic shift in trade policy is likely to have wide-ranging implications for multinational companies, which have strung factories and facilities across the North America to take advantage of NAFTA's terms. It could also portend changes for American consumers, who for decades have enjoyed cheap goods manufactured just over the border.

The specific effects on American businesses and consumers would hinge on the terms of the trade deals that replace it. But if tougher barriers to Mexican imports were to provoke retaliatory action by Mexico, the effect could be damaging to American manufacturing communities, said Hufbauer. "There would be a lot of localised pain of going down this path, and there may be some products that are suddenly more expensive than they otherwise would have been."

For Mexico, the ultimate goal in the trade negotiations with the United States is to maintain the flow of free trade that NAFTA has created between the two countries. The United States is Mexico's largest trading partner and the destination of 80 per cent of its exports.

"We want to arrive at an agreement," Foreign Minister Luis Videgaray told reporters on Thursday.