Mr Fox has told CTV News he is concerned Canadian PM Justin Trudeau seemed willing to “protect Canada even by sacrificing Mexico”.
Negotiators are in the midst of the fifth round of talks between the three partners on their North American Free Trade Agreement (Nafta).
In October, US President Donald Trump said he would consider a trade pact with Canada minus Mexico. Mr Trudeau said in response to Mr Trump that he still believes a renewed deal can be reached between the three partners. But he added that Canada has to “be ready for anything”.
In the CTV News interview, Mr Fox said that Mr Trudeau “might, like Judas, give us a strike and go with the United States and leave us aside. “I warn Trudeau and I warn Canada, you will not make it.”
The talks to update the 1994 deal have become increasingly acrimonious. Trade ministers from the three partner nations are not at the table for this round of talks to provide negotiators time to analyse the proposals that have been tabled thus far.
The hurdles for negotiators include US demands for tougher automotive content rules and a “sunset” clause that would require the trade treaty to be renewed every three years or expire.
Mr Fox, who served as Mexican president between 2000-6, has been an outspoken critic of Mr Trump, telling the BBC in February that the US president could “go to hell”.