A gasoline shortage that has left many Ontario filling stations out of fuel has spread to Quebec, sending pump prices higher.

At least 10 Montreal area Esso gas stations and one in Sherbrooke reported shortages on Monday.

With shortages in supply now cropping up in Quebec, some fuel companies are taking advantage of the situation by hiking prices. The price of regular gas jumped four cents a litre Tuesday morning in many areas of Montreal, to as much as $1.04 per litre.

The shortages began in Ontario following a Feb. 15 fire at Imperial Oil's Nanticoke refinery.

A strike by 2,800 conductors and yard-service workers at CN Rail exacerbated the problem. The workers recently returned to their jobs after a tentative deal was reached.

Joseph D'Cruz, a professor at the University of Toronto's Rotman school of management, said about 40 per cent of Ontario's gasoline supplies come from outside the province, and Quebec is a main supplier of gas to Ontario.

 "When there is a shortage somewhere, they use the railway to bring in supplies," he said.

With gasoline price climbing in the wake of the fire, Robert Théberge, a spokesman with Imperial Oil, tried to pin some of the blame on rising crude oil prices.

But oil prices have been relatively stable of late, and down from their recent highs.

"[Oil] companies watch retail prices, and demand and supply, very very closely," he said. "Any time there is an opportunity to raise prices because of local shortages, all of them take that opportunity."

Théberge did not offer a date on when the supply situation might be rectified.

"We hope that by the time the weekend comes, we will have seen a major improvement," he told CBC News.