OTTAWA -- Federal New Democrats are asking the Liberal government to provide Canadians with more information about what's in the new North American free trade deal and commit to regular reviews of its impact on the country after it comes into force.

The requests are in a Dec. 1 letter from NDP trade critic Daniel Blaikie to Deputy Prime Minister Chrystia Freeland, who last week signed a revised version of the Canada-U.S.-Mexico deal.

The agreement must now be formally approved by Parliament before it comes into force, which will require support from at least one opposition party.

Blaikie says the NDP wants the government to include its past proposals for making free-trade deals more transparent to Canadians in the new agreement.

New Democrats also want the government to seek the consent of any province where the deal would let a foreign investor use an international tribunal to challenge provincial laws instead of a Canadian court.

Blaikie does not say in the letter whether the NDP's support for the new North American trade deal will be contingent on the government adopting its demands.