Employers can no longer force workers to retire at age 65 in Ontario.
The province says legislation passed on Dec. 8 eliminates age-based discrimination and allows people to work as long as they want.
Premier Dalton McGuinty has said keeping some older workers on the job longer would also help the province's economy because it would draw upon their expertise.
But critics say the legislation will force people to work longer in order to qualify for pensions.
Similar legislation in the United States has resulted in people working until the age of 67 to get their pensions, says Wayne Samuelson, president of the Ontario Federation of Labour.
Mandatory retirement has already been lifted in Manitoba, Quebec, Alberta, Prince Edward Island, the Yukon and the Northwest Territories.