Vancouver has replaced Sydney as the world's second-least affordable city for homebuyers, according to an annual housing market survey.

The eighth Demographia International Housing Affordability Survey tracked 325 markets and found the most affordable nations to be the United States, Ireland and Canada – with some notable exceptions.

Of the 35 Canadian markets ranked, six were found to be "severely unaffordable." Four of those were in British Columbia.

The rankings were determined using a "median multiple," which divides median housing prices by residents' median annual before-tax income.

The world's least-affordable city, Hong Kong, had a median multiple of 12.6, while last year's runner-up, Sydney, was calculated at 9.2.

Vancouver, which was bumped up from its previous position as the world's third-least affordable city, had a median multiple of 10.6, with incomes at $63,800 and housing prices at $678,500.

"Vancouver, which like Sydney has largely prohibited housing development on the urban fringe for decades, experienced a significant deterioration," the survey said.

Other B.C. cities listed as severely unaffordable were Abbotsford (median multiple 7.0), Victoria (6.6) and Kelowna (6.6).

The most affordable major markets in Canada were found in Edmonton and Ottawa-Gatineau, which had median multiples of 3.5 and 3.7, respectively.

Windsor was the most affordable market in the country at 2.2.

Toronto was listed fifth least-affordable in Canada, with incomes at $73,600 and housing prices at $406,400 for a median multiple of 5.5. Montreal was ranked sixth, with a median multiple of 5.1.

The survey notes that the markets listed as severely or seriously unaffordable "were characterized by more restrictive land use regulation… which materially increases the price of land."

The authors list "compact development," "urban consolidation," "growth management," "smart growth" and "livability" policies as restrictive regulations.