TORONTO -- Vancouver has been ranked among the most unaffordable real estate markets in a recent international report, leaving economists concerned about the potential impacts of rising mortgage rates on the city's homeowners.

"Given how high house prices are relative to household incomes, you'd only have to see a moderate increase in mortgage rates to have a really huge hit to affordability," said economist David Madani of Capital Economics.

Only Hong Kong was rated less affordable than Vancouver in the annual Demographia International Housing Affordability Survey, which tracks 378 metropolitan markets in Canada, the United States, Australia, China, Ireland, Japan, New Zealand, Singapore and the United Kingdom.

The survey calculates affordability by comparing median house prices with median incomes -- the higher home prices relative to incomes, the more unaffordable the market.

Cities like Vancouver and Toronto, where house prices are significantly higher than incomes, would be hit hardest by a spike in mortgage interest rates, Madani said. Many homeowners could find themselves struggling to make monthly payments.

In Vancouver, the report said the median home price was $704,800, 10.6 times higher than the median household income of $66,400 in 2014. That's the worst affordability ranking Vancouver has ever received in the survey's 11-year history, and an increase from 2013 when prices were about the 10.3 times higher than incomes.

Meanwhile, the median home price in Toronto was $482,900, about 6.5 times higher than the median household income of $73,900 last year.

A report released Monday by TD Economics said a mortgage increase of two percentage points could cause financial hardship among Greater Toronto Area homeowners, pushing up the number of residents who devote 30 per cent of their income to mortgage payments to 20 per cent from 16 per cent.

Although Vancouver was the only Canadian city that made it to the Top 10 list, Toronto, as well as in Victoria, Kelowna and the Fraser Valley in B.C., were also ranked as unaffordable by the Demographia study.

Meanwhile, Moncton, N.B., was ranked Canada's most affordable market.

Fredericton and Saint John, N.B., Windsor, Ont., and Charlottetown were also ranked as affordable places to buy homes.

Overall, the study ranks Canada as "seriously unaffordable," with home prices in major urban markets about 4.3 times higher than incomes, while for Canadian real estate markets overall, median home prices are 3.9 times median incomes.

The Bank of Canada had been expected to raise its trend-setting interest rate, which has been at one per cent for more than four years, this fall. Economists now suggest that may be delayed, given the collapse in the price of oil and its likely impact on economic growth and inflation.

However, Madani says even if the central bank remains in a "holding pattern," Canadian mortgage rates could rise in response to economic recovery south of the border and policy actions from the U.S. Federal Reserve.

"We can expect the U.S. Federal Reserve to soon begin to raise interest rates, and with that we expect to see rising U.S. Treasury yields," Madani said. "On that basis, we have been expecting long-term interest rates in Canada to go up, and those rates are what really, in some sense, determine or influence mortgage rates.