Speculation by both Foreigners and Domestic investors is the reason why Vancouver/Toronto housing crisis occurred.     Tax them heavily. 

I have been saying this for years that most detached homes in my neighborhood are bought by speculators.   Some are rented out and some are empty .    Too many homes waiting to be flipped, causing temporary shortage of housing, driving rents up.    This vicious cycle can only be stopped by the Federal government imposing heavy tax on speculation.   

Also, foreign buyers' tax should be applied across the country, at 5~15% range depending on locations.   5% foreign buyer's tax in Winnipeg & Calgary won't affect the local market.