Quebec's intergovernmental affairs minister says his province agrees with the federal government that the Senate needs reform, but will mount a legal challenge if Ottawa brings in changes unilaterally.

In an interview airing Saturday on CBC Radio's The House, Quebec's Intergovernmental Affairs Minister Pierre Moreau said changes to the Senate cannot be made through a "unilateral law" from Prime Minister Stephen Harper's government.

"We do agree that the Senate should be reformed, but we do not agree on the way the speech [from the throne] proposes it will be done," Moreau told guest host Alison Crawford.

"It is clear for us that any change that would be made without the consent of the provinces would imply that we would go to the Court of Appeal here in Quebec."

One page of Friday's 16-page throne speech includes many of the items Harper and his party have discussed since first taking office as a minority in 2006, including Senate term limits and possibly elected senators, if the provinces and territories co-operate and hold elections.

When asked whether he was committing Quebec to a legal challenge if the Conservatives move forward unilaterally on Senate reform, Moreau replied: "Absolutely." He also suggested other provinces would follow suit.

"We're not the only province who thinks we need a constitutional agreement to make changes to the Senate," he said.

"The fact that there's a majority government in Ottawa doesn't change the constitution itself."