The United States and Mexico have already ratified the agreement and President Donald Trump held a signing ceremony at the White House Wednesday.

Mexico objects to legislation introduced in the U.S. Congress as part of an eventual ratification of the deal.

The United States-Mexico-Canada Agreement was signed in November 2018 but formal U.S. approval has been held up by Democratic lawmakers pressing the Trump administration for changes, including steps on drug protections.

Employment Minister Patty Hajdu will be in the meeting to try to address labour enforcement standard concerns.

Robert Lighthizer has agreed to refrain from sending Congress formal ratification language until the Democratic leader was ready to move forward.

Trump tweeted Thursday that on June 10 he will impose a five per cent tariff on all Mexican imports.

Dealing with the tariffs -- imposed by President Donald Trump under a controversial national-security provision of U.S. law -- is a key part of the CUSMA ratification process, Freeland said.