TORONTO -- Ontario drivers could soon see government-mandated stickers about the price of the carbon tax on gas pumps across the province, as the Progressive Conservatives open a new front in their battle with Ottawa over the levy.

The environment and energy ministers made the announcement Monday in one of the near-daily events the Ontario government has held to slam the tax since it was imposed one week ago.

"We will make sure that we use every tool at our disposal to make sure that Ontarians understand the impacts of this carbon tax -- the impact on their business, the impacts on their families and the impact on our province's competitiveness," Environment Minister Rod Phillips said at a gas station in Oakville, Ont.

Ontario will introduce legislation that would require stickers to be put on gas pumps showing that the tax has added 4.4 cents a litre to the price of gasoline and that will rise to 11 cents per litre by 2022. Each pump would be expected to display an English sticker and a French one.

Energy Minister Greg Rickford framed it as a transparency measure.

"The people of Ontario deserve to know the full truth about how the federal carbon tax will make their lives more unaffordable," he said. "It will hit our wallets hardest when it comes to gas prices and home heating costs and the businesses and programs and services that we use."

Rickford couldn't provide a cost for the move, but said it will be "very minimal."

Federal Environment Minister Catherine McKenna said Ottawa's plan is an affordable way to fight climate change, and criticized Ontario Premier Doug Ford for the stickers.

"The Ford government will be spending taxpayers' dollars on stickers that intentionally mislead Ontarians about our plan, and do not include the amount of money that people are getting back, or the cost of inaction on climate change," she said in a statement.

"It's clear that Doug Ford cares more about wasting taxpayers' dollars on misleading stickers, than on helping Ontarians save money and energy, or on coming up with a meaningful climate plan."

The carbon tax is expected cost to a typical household $258 this year and $648 by 2022. Residents of provinces with the tax will be getting rebates on their income tax returns that start at $128 annually and increase for people with spouses or dependents at home. The federal government says a family of four in Ontario would get $307 this year.

Ontario is one of four provinces, including Manitoba, Saskatchewan and New Brunswick, where Ottawa imposed the levy because they opted not to impose their own pricing schemes on carbon emissions.

Green party Leader Mike Schreiner said he is "appalled" at the time, resources and money being wasted on an "anti-climate campaign."

"If the government truly cared about transparency, they would put stickers at the pumps that outlined the costs of the climate emergency that we face," he said in a statement.

Greenpeace Canada said it would challenge the Ontario government's stickers under the Canadian Code of Advertising Standards.

"By omitting both the costs of climate change and information on the federal rebates, we believe that these stickers would violate the provision of the code that states 'Advertisements must not omit relevant information if the omission results in an advertisement that is deceptive or misleading,"' the advocacy group said in a statement.

The government has also asked the Ontario Energy Board to clearly reflect the cost of the carbon tax on natural gas bills. It will add about four cents to a cubic metre of natural gas.

Ontario is challenging the carbon tax in court next week.

While Ford has said he is staying out of the upcoming federal election, he has taken pains to brand the carbon pricing scheme as the "Trudeau Liberal carbon tax" and cast doubt on the rebates.

The federal tax is $20 a tonne for this year and is set to increase by $10 annually until it reaches $50 a tonne in April 2022.