The increase in gas prices was the largest since the 34.7-percent gain reported for September 2005, when hurricanes Katrina and Rita disrupted the oil market, the report said. In the 12 months ending in June, gas prices rose 26.9 percent.

If gasoline weren't a factor, June's CPI increase would have been 1.8 percent, StatsCan said.

Mortgage interest cost, bakery products and air transportation also exerted strong upward pressure on the index, with mortgage interest costs rising 9 percent.

The cost of bakery products rose 12.3 percent, while the price of air transportation rose 14.3 percent, with fuel costs being the major factor.

Purchase and lease prices for passenger vehicles fell 8.4 percent from June 2007 to June 2008. Prices for computer equipment and supplies dipped 13.2 percent, the report said.