If that doesn't happen, Marois says she'll introduce back-to-work legislation.
In the meantime, she appointed a new mediator on Monday to help the two sides reach a deal.
"It's always better for the two sides to reach an agreement rather than introduce back-to-work legislation," Marois told reporters in Quebec City.
"We want people to come back to work happy and be productive."
About 175,000 construction workers in the residential, commercial and industrial sector have been off the job since last Monday. Talks between the unions and an alliance of construction companies broke off past midnight on Sunday after a lengthy weekend negotiation session.
The main sticking points include wages, overtime, and labour mobility.
But Marois said there's reason for optimism after an agreement in principle was reached Monday for the 41,000 people who work on the province's roads.
The construction strike has stalled work on Montreal's two megahospitals, which are among the biggest construction projects in Canada.
It's also causing concern for people waiting to move into new homes and condos. July 1 is Quebec's traditional moving day.
Marois had hinted last week that she could introduce back-to-work legislation before departing on a work mission to Mexico this Wednesday.
On Monday, Marois told reporters she wanted to avoid taking that step and would be prepared to wait another work week.
Marois said she will have to take action if the strike stretches beyond 10 working days.
Yves Ouellet, a spokesman for the construction unions, said he's hopeful a deal can be reached with the help of the mediator before they get forced back to work.
"We are ready to co-operate to reach an agreement," he said. "At the same time, we will not change our position, one that's shared by our workers and their families."
— with files from Alexandre Robillard and Pierre St-ArnaudSuggest a correction