Ottawa motorists will want to fill up the gas tank today before prices rise again on Wednesday. Gas is selling for around $1.70 a litre at stations in Ottawa on Tuesday. Canadians for Affordable Energy president Dan McTeague says gas prices are expected to increase 4 cents a litre on Wednesday, and “likely another 2 to 3 cents increase on Thursday.” Prices are expected to rise to 174.9 cents a litre in Ottawa on Wednesday. Diesel prices are expected to increase 9 cents a litre in Ottawa on Wednesday to $2.32, according to McTeague. Gas prices hit a high of $1.96 a litre in the capital in May due to the ongoing conflict in the Middle East.