TORONTO - The Ontario government says it will be moving forward with a constitutional challenge to a federal plan to impose a carbon tax on provinces that don't have their own carbon pricing system.

Environment Minister Rod Phillips and Attorney General Caroline Mulroney made the announcement in Toronto this morning.

They said the constitutional challenge is in addition to Premier Doug Ford's decision to join a similar legal battle launched by the government of Saskatchewan.

Ford vowed to fight Ottawa's carbon pricing plan and eliminate Ontario's cap-and-trade system during the spring election campaign.

His Progressive Conservative party's platform budgeted $30 million for the court challenge and Mulroney said she believes it will cost less.

Ford's government has introduced legislation to scrap cap and trade and cancel programs financed through its revenues, which include rebates for energy-efficient renovations, transit projects and a fund for school repairs.