Asked whether Premier Kathleen Wynne's Liberals could win an election with an Ontario Retirement Pension Plan, Harper said increasing taxes isn't the way to go.
He says people prefer to get tax breaks for socking away money for retirement, not having their taxes hiked to force them to save.
Harper says his government has offered those tax breaks and created a number of voluntary retirement savings programs.
But the provincial Liberals, who are headed for an election, say they have to move ahead because Harper won't enhance the national Canada Pension Plan.
The made-in-Ontario plan would require contributions from both workers and employers, which the provincial Conservatives have denounced as a payroll tax that will kill jobs.
Wynne has called Harper's refusal to change the pension plan "offensive and inexplicable" because Canadians aren't saving enough to ensure they have a comfortable retirement.
Prince Edward Island and Manitoba are banding together with Ontario to explore options to enhance retirement income, saying they're disappointed with the federal government's unilateral decision to shut down discussions on enhancing CPP.
Ontario released a blueprint for their pension plan in Thursday's budget, but left the door open to expanding the program to other provinces and even suggested it could be integrated into the CPP in the future.
While the Liberals said a CPP enhancement was still Ontario's "preferred approach" to strengthening the retirement income system, the new provincial plan was touted as the next best thing as governments deal with aging populations and people who aren't saving enough for the future.
It will likely be a key part of the minority Liberals' election platform, as the New Democrats have vowed to vote against the budget.
The ORPP was billed Thursday as a mandatory plan that will be modelled on the CPP, which provides retirement benefits to contributing workers up to a maximum of about $12,500 annually.
Ontario's plan, however, won't apply to all the province's workers — those with "comparable" workplace pension plans, federally regulated employees and those with income below a yet-to-be-determined threshold would be exempt.
The government said it is still consulting on how it can help self-employed individuals, who currently aren't part of the plan, to better save for retirement.
The exemptions mean the plan will initially involve about three million Ontario workers when it launches in 2017.
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