The Canadian and Mexican ministers railed against aggressive US demands that would help boost US trade but diminish their own markets.
But despite the widespread disagreements at the talks in Washington, both Canada and Mexico vowed to keep negotiating to avoid an en impasse.
The Trump administration’s proposals to reshape NFTA to help shrink US trade deficits have clouded the talks to modernise the 23-year pact.
US negotiators rolled out a raft of proposals urging Canada to dismantle its system of protections for the dairy and poultry sectors, a move that Ottawa will reject.
Additionally, the Trump administration set out proposals that could impose fresh restrictions on long haul trucking from Mexico.
That too is likely to meet stiff resistance, Mexican officials say.
Washington’s demands, previously identified as red lines by its neighbors, include forcing renegotiations every five years.
It also wanted to reserve the lion’s share of automotive manufacturing for the United States and make it easier to pursue import barriers against some Canadian and Mexican goods.
Mexican and Canadian officials at the talks have said that these proposals are unacceptable.
Moises Kalach, head of the international negotiating arm of Mexico’s powerful CCE business lobby, said America’s demands were “ridiculously extreme.”
He said: “The key is to remain calm and see if the American government is ready to negotiate.”
Now fears are growing that negotiations to modernize NAFTA, which underpins some $1.2 trillion in annual trade between the three countries, could even extend into March.
It is yet to be seen how Mr Trump will react to the stumbling blocks.
During his 2016 presidential campaign he pledged to “bring back jobs” and reinvigorate the US manufacturing sector.
Since taking office, he has continued his attacks on NAFTA even going so far as to threaten to terminate it if Mexico and Canada will not agree to changes.
US Trade Representative Robert Lighthizer, said that the tough negotiations reflect the US President’s desire to claw back lost US manufacturing jobs.
He said Mr Trump’s main aim was to slash the US goods trade deficits which amounted to $64 billion with Mexico and $11 billion with Canada last year.