Marois says she spoke with representatives from construction unions and companies on Saturday and asked them to give negotiations one last try.
But talks between the two sides broke off Saturday evening.
"I'm very disappointed to have to introduce a special law," Marois told reporters Sunday on her way inside the provincial legislature, which reconvened for a special sitting to deal with the construction strike.
"Honestly, we really wanted to get this done through negotiations and discussions."
The back-to-work legislation was expected to pass in the early morning hours on Monday after a lengthy day inside the legislature.
Some 77,000 workers in Quebec's industrial, institutional and commercial construction sectors have been on strike since June 17.
Workers in other sectors, including residential construction and road work, were able to reach deals last week.
The bill introduced Sunday morning would mean an agreement along the lines of the one reached in the civil engineering and road construction sector. Wages would increase by two per cent in the first year, 2.1 per cent the year after, 2.2 per cent in the third year and 2.3 per cent in the final year.
If the special law passes, striking workers would have to be back on the job by Tuesday.
The PQ has faced criticism from some in its base who say the party has not done enough to support the unions.
The opposition Liberals and Coalition party were both in favour of introducing back-to-work legislation, but criticized the Parti Quebecois government for not providing the details of the bill in advance.
Jean-Marc Fournier, the Liberal house leader, accused the PQ of failing to act quickly enough. He said the strike has caused unnecessary delays and the economic consequences will be significant.
The construction strike has stalled work at sites across the province, including work on Montreal's two super hospitals.
— with files from Patrice Bergeron in Quebec City.
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