Eight thousand support staff at Ontario colleges walked off the job early Thursday at the start of the academic year, after last-minute contract talks failed.
The striking OPSEU workers include everyone from administrators to maintenance and library workers, meaning students may be in for significant disruptions to some services.
All 24 colleges will remain open with classes and registration running.
Management and part-time support staff who are not part of the striking unit will take over vital duties during the strike.
George Brown College in Toronto, for instance, warned students that child care, career counselling and sports would be suspended. Others were concerned that picketing would slow down access to campuses.
"We expect that there will be delays getting into the campuses and that there will be probably slow downs in regards to the services that are provided on campuses but we do expect that the colleges will remain open," Rod Bemister, chairman of the OPSEU bargaining committee, said early Thursday.
The Ontario Public Service Employees Union sought a 3 per cent raise in each of the next two years and fought a proposal to extend probationary periods from six months to 12.
The colleges, represented by the College Employer Council, maintained that the union's wage and benefit proposals were unaffordable. It countered with an offer that would have granted a 4.75 per cent raise over three years.
Gerry Barker, chairman of the colleges' bargaining team, said the colleges offered increases for support staff that would take the average salary to more than $59,000 a year with no concessions.
"Very, very disappointed that we were not able to reach an agreement. I honestly believe that what we put on the table was a good and fair offer," Mr. Barker said in an interview with The Canadian Press.
But the union said it went on strike because the colleges demanded concessions and clawbacks to its existing contract.
"We tried to reach an accommodation with management negotiators but it became very clear as we approached the strike deadline that they were not prepared to meet us on terms we could accept" Mr. Bemister said in a release.
"We are prepared to return to negotiations at any time but management must adopt a fresh approach."
The strike also comes on the eve of a provincial election campaign in which Dalton McGuinty's incumbent Liberal administration will attempt to win a third mandate, in part on a record of relative labour peace.
Ontario Federation of Labour president Sid Ryan chimed in on the labour dispute early Thursday by saying OPSEU is "taking a courageous stand to protect the future of work in Ontario."
Mr. Ryan will join striking support staff Thursday at Durham College campuses in Whitby and Oshawa.
OPSEU president Warren (Smokey) Thomas will also join striking staff at a rally Thursday at a downtown Toronto campus of George Brown College.
The union was in a legal strike position as of Thursday, and the two sides continued negotiating Wednesday evening.
With reports from James Bradshaw and The Canadian Press