Toronto's 23,000 inside workers could be off the job as early as 12:01 a.m. March 24, shuttering city-run swimming pools, recreation centres, daycares and other municipal services.

The province has granted the city's request for a "no-board" report, kicking off a 17-day countdown to a strike or lockout of members of CUPE Local 79, the city's largest union.

The March 24 deadline is less than a week after a March 18 deadline for 2,300 library workers, meaning Toronto is now barrelling toward labour disruptions on two fronts.

Story continues below advertisement

"We're always concerned about a strike, but we're still optimistic that one won't happen and that an agreement can be reached," said Deputy Mayor Doug Holyday, the mayor's point man on labour relations.

The members of CUPE Local 79's four bargaining units have been without a contract since Dec. 31, 2011.

Negotiations, ongoing since last fall, are continuing.

Tim Maguire, the president of Local 79, and Maureen O'Reilly, the president of Local 4948, which represents library employees, say working conditions for part-timers continue to be a stumbling block to a new collective agreement.

Story continues below advertisement

For example, they say the city has proposed removing workers' access to hours by seniority, a change that could mean fewer, more scattered shifts for experienced part-timers.

Mr. Maguire added Thursday that the city has threatened to reduce by five the number of hours per week for full-time staff at old-age homes.

"[That]means a cut in income of nearly 7 per cent," Mr. Maguire said, adding the move would eliminate an overlap between shifts, when workers exchange daily information about their patients.

"It's important for us, it's important for the public, to have that kind of interface between caregivers in caring for our grandparents and our parents," Mr. Maguire said.

Story continues below advertisement

Earlier this year, the city struck a deal with the union representing 6,000 outdoor workers, including garbage collectors.

CUPE Local 416 secured a 6-per-cent pay hike over four years, but the union sacrificed job security for members with less than 15 years of experience.

City services that could be affected by a strike or lockout:

-daycares

Story continues below advertisement

-building permits

-park permits

-recreation programs

-city-run museums

-events at Nathan Phillips Square and other civic centres

Story continues below advertisement

-libraries (if CUPE Local 4948, representing library workers, strikes or is locked out.)

Source: City of Toronto. (If a labour disruption appeared imminent, the city would release a more detailed list of what is open and closed.)