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There was an "absurd and unjustified" increase in prices at the pumps early Wednesday in several parts of Canada, a leading consumer advocate says.

Montreal saw the sharpest increase: about 13 cents per litre to about $1.53.

Cities in southern Ontario saw an average increase of about 3.4 cents per litre — to about $1.36 in Toronto and vicinity — and prices in Ottawa increased to about $1.34. The cost of gas spiked by 11.6 cents per litre in Peterborough, Ont., to about $130.9.

The price in Vancouver is up 5 cents per litre to about $1.36, and in Victoria 6 cents per litre to about $1.28.

The figures come from the website tomorrowsgaspricestoday.com, run by former MP and consumer advocate Dan McTeague, who has long tracked gas prices and lamented what he calls "a lack of competition in Canada's energy sector."

"Increases of this magnitude would suggest a major international event or supply disruption, neither of which can be considered since they have already been factored in over the last few weeks (ex: hurricane Isaac )," McTeague said on the site.

He predicts another increase by the weekend because the U.S. government is expected to announce another economic stimulus package this week, which will raise the price of commodities like oil and motor fuel.