FREDERICTON -- New Brunswick's environment minister says Ottawa's plan to impose a carbon tax on the province's consumers defies logic.

Andrew Harvey says New Brunswick has the highest tax on gas and diesel of any province in the country, but the federal government is saying it has to do more.

Ottawa asked all provinces to put a minimum price of $20 a tonne of emissions by Jan. 1.

The tax will be imposed in April on New Brunswick, Saskatchewan, Manitoba and Ontario -- the provinces which have not signed on to the plan.

Prime Minister Justin Trudeau said Tuesday that Ottawa will return 90 per cent of the money it collects from a carbon tax back to Canadians.

New Brunswick's Liberal government had proposed to repurpose some money already collected in gasoline taxes in lieu of a new carbon tax.

"We've done enough in New Brunswick with taxes and consumers in New Brunswick shouldn't be paying any more in tax," Harvey said Tuesday.

"We have a higher price than a province like Alberta. They are penalizing New Brunswick but not penalizing Alberta, it defies logic, the federal approach here. We don't accept it at all," he said.

New Brunswick is in a state of flux because no party won a majority in last month's provincial election.

Tory Leader Blaine Higgs, who could become premier early next month, has said he refuses a carbon tax and will join a lawsuit with other provinces if he takes office.

However on Tuesday, Higgs said he wanted to take a closer look at the federal proposal.

"We oppose any carbon tax of any kind, but what we have said in the same vein, we have said we will ensure New Brunswickers get a full rebate. We're interested in getting more details on what the federal government has proposed, but our goal is that New Brunswickers will not pay any additional tax," he said.

New Brunswick's Green leader, David Coon, said he's pleased the federal government is moving on the carbon tax right across the country, but says the Trudeau government is giving big polluters a "free ride" by only making them pay the tax on between 10 and 20 per cent of their emissions.

In PEI, the province and the federal government announced a two-year agreement.

"This plan will meet our climate change targets and not cost Islanders any more. In fact, Islanders will continue to save through our incentives," the province said in a news release. "As a result, home heating fuels on Prince Edward Island will be exempt from any price on carbon. This means that thanks to our plan, Islanders will not pay more to heat their homes. Keeping taxes off home heating is something our government has championed. This plan will save Islanders $38.7 million directly."