Approximately 20,000 part-time support staff at the province's colleges have voted to join the Ontario Public Service Employees Union.

OPSEU says 84 per cent of the ballots counted were cast of in favour of joining the union.

It says the supervised vote at all 24 Ontario community colleges was held in June 2016, but legal wrangling by the College Employer Council kept ballots from being counted until this week.

OPSEU president Warren (Smokey) Thomas called the vote "a magnificent victory for part-time college support staff and for all the people who worked hard for so many years to win union rights for them."

OPSEU has long represented full-time staff at the colleges, but it was illegal for part-time employees to organize.

The union says a campaign it began in 2004 resulted in the provincial government amending the Colleges Collective Bargaining Act in 2008 to grant them the right to unionize.