"We are cautioning people not to assume too much long-term debt on the assumption that interest rates will stay as low as they are -- because they won't," Flaherty said Sunday on CTV's Question Period.
"We want to make sure Canadian households plan ahead and know, if they renew a mortgage in the next several years, it's likely that the interest rate will be higher," he added.
"Interest rates have nowhere to go but up."
Flaherty's remarks echo those of a Bank of Canada report last week that said high household debt is now the most significant risk to the Canadian economy.