The Ontario government says it has taken the next step in its legal challenge against the federal government’s carbon tax plan.

Environment Minister Rod Phillips says the government has filed a statement in court outlining its arguments that Ottawa’s carbon pricing plan is unconstitutional.

The province argues the federal government does not have the power to put a price on greenhouse gases because provinces are able to regulate them themselves.

It also alleges the charges imposed under the federal plan are “unconstitutional, disguised taxes” because the legislation does not require the funds to be used for the reduction of greenhouse gas emissions

Premier Doug Ford vowed during the spring election campaign to eliminate Ontario’s cap-and-trade system and fight the planned federal tax for provinces that don’t have their own carbon pricing regime.

His government has since passed a regulation and 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.

Greenpeace Canada filed a legal challenge against the province this week over the lack of consultation on those decisions, and the Progressive Conservative government posted a notice of consultation on the Cap and Trade Cancellation Act hours later.

The group says it is still proceeding with the suit – one of several legal battles the province is waging.

Earlier this week, a judge struck down provincial legislation to reduce the size of Toronto’s city council, saying it violated the constitutional rights of candidates and voters.

The province is appealing the ruling, and also took the unprecedented step of overriding it by invoking a rare constitutional provision. The move set off a wave of outrage from critics who have said the notwithstanding clause invoked by Ford was not designed to deal with such an issue.