Trudeau made the comments while speaking in North York about his government’s GST family credits.
“It is a very, very serious thing to suspend people’s fundamental rights and freedoms,” he said.  “The preemptive use of the derogation clause is actually an attack on people’s fundamental rights and, in this case, it is an attack on one of the most basic rights available – that of collective bargaining.”
“I think there are a lot of people, a lot of parents like me, who have kids in Ontario schools who are concerned about the job action, about the strikes, but I can tell you that all parents, all parents, should be extremely we are concerned about the suspension of our most fundamental rights and freedoms.”
He added that the federal government is considering “all options” to protect those freedoms.  However, he did not elaborate on what those options might be.
It’s not the first time Trudeau has spoken out against Bill 28, an Ontario law passed Thursday that uses the nullity clause to override parts of the Charter of Rights and Freedoms to make it illegal for workers to strike.
The bill also legislates a four-year contract to the 55,000 members of the Canadian Union of Public Employees (CUPE), which includes custodians, administrative staff and education support workers.
Earlier this week, Trudeau called Ontario Premier Doug Ford and told him the use of the extension clause was “wrong and inappropriate.”
The derogation clause is part of Section 33 of the Charter of Rights and Freedoms and gives provincial governments the ability to override certain parts of the charter for a five-year period.
Ford, for his part, used the clause rather liberally.  He first threatened to use it in 2018 to reduce Toronto city council seats during a municipal election, then invoked it to restore parts of the election finance law in 2021.
In the case of Bill 38, the Ford government argues that it is necessary to keep schools open and prevent disruption for children.
“The outrage that we’re seeing across the country right now at this latest use (of the notwithstanding clause), based on past uses that I’ve consistently condemned, I think it’s a moment for all Canadians to think and say, ” yes, our fundamental rights should not be abrogated by governments that want to do things the easiest and most efficient way possible at the expense of people’s fundamental freedoms,” Trudeau added Friday.
Ontario is also applying to have the strike and union leaders’ actions declared illegal by the Ontario Labor Relations Board.