OTTAWA (Reuters) - Top U.S., Canadian and Mexican officials are in constant contact about slow-moving talks to revitalize NAFTA and are ready to meet at any time to push the process forwards, Canada’s foreign minister said on Tuesday.

FILE PHOTO: The flags of Canada, Mexico and the U.S. are seen on a lectern before a joint news conference on the closing of the seventh round of NAFTA talks in Mexico City, Mexico, March 5, 2018. REUTERS/Edgard Garrido/File Photo

Negotiations to update the North American Free Trade Agreement have stalled as Canada and Mexico try to digest U.S. demands for major changes.

U.S. officials have said some kind of a deal is needed in the next few weeks to prevent the negotiations spilling into campaigns for a Mexican presidential vote on July 1 and mid-term elections for the U.S. Congress in November.

Foreign Minister Chrystia Freeland said she had spoken on Monday with her counterparts driving the file - U.S. Trade Representative Robert Lighthizer and Mexican Economy Minister Ildefonso Guajardo - and they had agreed to meet if necessary.

“That was one of the things we talked about yesterday -- all of us are able to get on a plane and meet at the moment when that could bounce the negotiations (forwards). So we are in very close, I would say constant, touch,” she told reporters.

U.S. Treasury Secretary Steven Mnuchin on Monday said major issues remained between the NAFTA nations.

Canada and Mexico are struggling to accommodate U.S. demands for tougher rules of origin that dictate how much of a car must be produced in NAFTA nations to quality for duty-free status.

“I personally do believe that an agreement on rules of origin is really achievable but it is also the case that nothing is done until everything is done,” said Freeland.

A U.S. official said no meetings between the three top ministers were currently scheduled.

The administration of U.S. President Donald Trump, who has regularly threatened to pull out of the 1994 agreement, also wants higher wages in the auto sector.