Quebec's chief NAFTA negotiator says there would not be a new NAFTA deal today if Canada had refused to make concessions on the dairy industry.

"It became very clear that the president of the United States would never make a deal if he didn't get something strong from automobiles from Mexico ... and in milk in Canada," said Raymond Bachand in an interview with CBC News Network's Power & Politics.

Under the United States-Mexico-Canada Agreement (USMCA), American dairy farmers will have have access to 3.59 per cent of Canada's dairy market.

Bachand said the decision to give up that market access to the Americans was only made in the final weeks of negotiations.

"I think that was decided in the last two weeks," said Bachand. "There was strong resistance and basically protection of supply management throughout the negotiations."

Prime Minister Justin Trudeau has promised farmers they will be compensated for losses caused by USMCA.

Further access to Canada's dairy market was also given to foreign farmers in two other trade deals — the Comprehensive Economic and Trade Agreement (CETA) with the European Union and the Comprehensive and Progressive Trans-Pacific Partnership (CPTPP).

"If you take the three agreements together, basically dairy farmers have lost eight to ten per cent of their market over a five year period," said Bachand. "That's a big loss, and I think we as Canadians have to compensate and maybe invest in modernizing our farm system so it would be more productive."

The federal government has also been criticized for reaching a deal without securing an exemption from U.S. steel and aluminum tariffs.

Bachand said he's hopeful that issue will be resolved in the coming weeks.

"I think the pressure's building in the United States for them to get rid of them because it's hurting them," he said. "But I think you wouldn't have had a deal Sunday if we had insisted on doing that at that point in time."