FREDERICTON -- New Brunswick gas prices jumped by more than four cents a litre Monday, with one expert predicting the federal carbon tax could push motorists across the province's borders looking for cheaper gas.

New Brunswick is among four provinces that refused to impose their own emissions pricing, so Ottawa imposed a tax as of Monday.

Gas prices rose 4.42 cents per litre plus HST. Diesel jumped 5.37 cents per litre, and home heating fuel jumped 5.37 cents per litre.

The New Brunswick government said P.E.I. is paying just a penny more per litre of gas in carbon tax, and it's less than half that in Newfoundland and Labrador. Nova Scotia is also estimated to face an extra penny per litre.

"This carbon tax is like a very bad April Fool's joke," Jeff Carr, provincial minister of environment, said in a statement. "But unfortunately, the fact is that New Brunswickers are being hit with the highest carbon gas tax in Atlantic Canada."

Carol Montreuil of the Canadian Fuels Association said the patchwork system of carbon pricing plans across the country is especially pronounced in the Atlantic region given the relatively low increases in the provinces that neighbour New Brunswick.

Montreuil said rising costs in New Brunswick could potentially drive consumers over nearby provincial borders for cheaper fuel.

"People are very, very sensitive to retail prices," Montreuil said from Montreal.

"To what extent will consumers drive long distances to take advantage of a difference of four to five cents? No one knows, but it is an important number," he said.

Truck drivers, he noted, could choose to fuel up in other provinces along their route.

Premier Blaine Higgs' Tory government argues the tax will punish the many rural New Brunswickers who can't ditch their vehicles for public transit.

Carr said in an interview New Brunswick can fight climate change without raising taxes.

"This is a global issue and we're not opposed to taking our precautions here in New Brunswick and doing what we can and doing our part, but we don't need a tax to do that here," Carr said.

New Brunswick is an intervener in legal challenges launched by Saskatchewan and Ontario in its fight against the carbon levy.

Liberal MLA Andrew Harvey, a former environment minister, said his party encourages Higgs to negotiate with the federal government rather than take the issue to court.

Residents of the four provinces will be getting rebates as well on their income tax returns. The rebates start at $128 annually, vary between provinces and increase for people with spouses or dependents at home.

David Coon, leader of the provincial Greens, said the federal government has failed to properly educate Canadians on climate change and said the carbon tax lacks an effective outlet that would use the revenue to help individuals reduce their carbon footprints.

"This has been, botched, in my view, provincially and federally," said Coon. "I don't see much cause for optimism with the two old parties in terms of how they're approaching the climate emergency, neither of them seem to be taking it very seriously."

In a visit to the province Thursday, Prime Minister Justin Trudeau criticized Higgs' Tories and other Conservative provincial governments who "don't think that fighting climate change is a priority."

"I regret that the government of New Brunswick doesn't think that putting a price on pollution is important," Trudeau said. "It's the 21st century. We know climate change is real. We know that one of the challenges we have is that pollution has been free. We need to put a price on it."

The federal government says the carbon tax is a sensible way to protect the environment - put a price on activities that pollute to discourage emissions, and give back most or all of the money through income taxes.

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.

-- By Holly McKenzie-Sutter in St. John's, N.L.