More than 55,000 education workers in Ontario have walked off the job, pledging to strike for “as long as it takes” in defiance a “draconian” new law amid a bitter fight with the provincial government over pay. The Canadian Union of Public Employees, which represents custodial staff, early childhood education and education support workers, launched the strike on Friday, despite legislation fast-tracked by the Ontario premier, Doug Ford, that bars it from striking and unilaterally imposes a contract on employees. Ontario’s conservative government has also dug in, saying it is unwilling to back down against an “illegal strike”. “Nothing matters more right now than getting students back in the classroom and we will use every tool available to us to do so,” the provincial education minister, Stephen Lecce, said in a statement. Ontario fast-tracked passage of Bill 28 earlier this week, which fines striking workers C$4,000 ($2,955; £2,260) a day – nearly a full month’s salary for the average employee. The law also fines the union C$500,000 a day. The union estimates the strike could cost nearly $C200m a day. Lecce has said the government would pursue collection of the fines. The legislation also imposes a contract on the union that includes 2.5% annual wage hikes for workers earning less than $43,000, and 1.5% for those earning more. The union had initially asked for an 11.3% raise for workers, citing stagnant wage growth and high inflation. Talks collapsed earlier this week, even after the union cut its wage proposal by more than half. The provincial government said it wouldn’t negotiate unless the union called off its planned strike. Ontario’s actions have caused concern from civil rights groups and federal leaders. When it passed Bill 28, stripping away the right to strike and unilaterally imposing a contract on education workers, it invoked the constitution’s notwithstanding clause, shielding the law from a court challenge and giving the union little recourse. Justin Trudeau tweeted that he spoke with Doug Ford on Thursday and expressed his frustration that the premier’s actions were “ wrong and inappropriate”. Ford responded that his government would pass the legislation to “keep classrooms open and ensure stability” for parents and students. “An important piece of the Charter of Rights and Freedoms is being shredded before our very eyes,” the Canadian Civil Liberties Association, warning that Bill 28 shatters the norm of governments restraint in invoking the clause and putting other rights – free speech, freedom of religion – at risk. The Ontario government has petitioned the labour board to force workers back, but Laura Walton, president of the Cupe Ontario school board council said staff will only return to work when a deal is reached or members decide otherwise. Walton also told parents to draw up childcare contingency plans for next week.