In a speech, Couillard told party members gathered for a meeting in Trois-Rivieres not to be distracted by those fighting the changes.
"Will there be obstacles? Yes. Should we agree, however, with those seeking to distract us by refusing to see the reality in which we live, or trying to create confusion and anxiety? No," Couillard said.
The premier delivered the message as hundreds of union members demonstrated outside the convention centre against a plan to restructure the pension plans of municipal workers, including police officers and firefighters.
Union spokesman Marc Ranger denounced the comments, saying Couillard's honeymoon as premier was nearing its end. Ranger said the government must be willing to compromise.
Quebec provincial police, along with municipal officers from Trois-Rivieres — who wore red caps in solidarity with the protesters — were on hand for security. The demonstration took place peacefully.
Couillard said returning to a balanced budget won't be easy but contended the "majority of Quebecers" understand the importance of the task.
"We listen to all voices in our society. We also listen to the quietest voices, working families who hope the government will do what it said it would do — that is to say, put the public finances in order and ensure a better future for their children," Couillard said.
The coming months will be a challenge for the Couillard government, with negotiations ahead to renew collective agreements involving 550,000 workers in the public and broader public sectors.
The labour union leading those talks is demanding increases of more than 4.5 per cent over three years.
But the Quebec government won't have the means to grant salary increases next year, said Finance Minister Carlos Leitao.
"No, it's very clear in the budget," Leitao told reporters.
"We limited total program spending in 2015-2016 to 0.7 per cent. We know that 60 per cent of program spending is compensation. Do the math."
Martin Coiteux, the president of the Quebec Treasury Board, didn't rule out a wage freeze in 2015-16, the year the government has targeted to return to a zero deficit, saying, "absolutely everyone will make an effort."