Builders picked up the construction pace in August, breaking ground on new condos at a breathtaking speed and pushing the annual pace of overall housing starts up to its highest level since September 2012.

The Canada Mortgage and Housing Corporation said Wednesday that a surge in multiple units pushed Canada's housing starts figure to its highest level of the year in August, at 196,565.

"Housing starts have been trending up, supported by strong condominium activity in Toronto," CMHC's chief economist Bob Dugan said.

Developers broke ground on 23,400 more units in August than were already underway in July — almost a 20 per cent increase.

Much of the rise in the national figure is tied to Ontario, the housing agency said. Ontario's housing starts figure increased by 43,500 across all types of housing.

"Never underestimate Canada's housing sector's ability to surprise to the upside," TD Bank economist Leslie Preston said of the numbers. "Or perhaps more precisely in August – Toronto's housing market."

While national starts have increased, housing construction has started to slow in Alberta and Saskatchewan as a result of weakening economic conditions related to the decline of oil prices, the CMHC said.