Ottawa is the least expensive big city in which to live in Canada, while Toronto is the most expensive, according the latest survey by the consulting firm Mercer.

Toronto takes over the dubious most-expensive honour from Vancouver, which was rated most expensive in 2010.

The survey looked at areas such as housing, transport, food, clothing and entertainment.

On an international scale, Ottawa ranks as the 114th most expensive city, while Toronto ranks 59th, Vancouver 65th. Montreal and Calgary are 79th and 96th respectively.

The cost of living survey is designed to help companies and governments calculate compensation allowances for expatriate employees.

The most expensive cities in the world for expatriates are Luanda, in Angola, and Tokyo. The cheapest is Karachi in Pakistan.