NIAGARA FALLS, Ont - Ontario's largest union says it will support a massive labour disruption if the province moves forward with plans to make public services essential.

The Canadian Union of Public Employees says the issue came up during last week's 45th annual convention in Niagara Falls.

During a debate, more than 1,000 delegates made it clear they would not tolerate workers' bargaining power being compromised by local or provincial politicians.

President Sid Ryan says CUPE will draw a line in the sand if Premier Dalton McGuinty tries to take away the right to strike.

The issue arose last month, when McGuinty suggested making the TTC an essential service.

The move came after Toronto transit workers walked off the job one weekend last month.