The union representing the city’s indoor workers says its members will begin a work-to-rule campaign Monday morning.

At a news conference Sunday night, CUPE Local 79 President Tim Maguire said “our goal is not service disruption,” but the union will enforce a work-to-rule campaign.

The campaign will include workers taking their breaks and restricting their duties to only those outlined in their job description, Maguire said.

The bargaining is expected to continue Monday morning.

 Earlier on Sunday, Maguire told reporters that he is “concerned by the slow pace of these talks.”

On Saturday, a strike deadline was extended to 12:01 a.m. Monday. It is the second time contract talks with the inside workers’ union have been extended by 24 hours.

 “There has been some improvement on some issues, but it’s not quickly enough,” Maguire said.

In a statement, Toronto Mayor John Tory said he is “disappointed that Maguire has chosen to threaten to escalate this unnecessary job action.”

He added that “such an escalation will not assist the efforts being made” to reach a collective agreement.

Tory also said that the city’s bargaining team will continue to work with the provincial conciliator to “achieve a resolution of these negotiations.”

Local 79 represents 21,000 of the city’s indoor workers, including those employed at childcare centres, libraries and Toronto Community Housing.

On Friday, CUPE Local 416, which represents the city’s outdoor workers, reached a tentative deal with the city.

Both unions have been without a contract since the end of 2015.