Ottawa is considering new measures to tighten mortgage standards and prevent would-be homebuyers from taking on more debt than they can afford.

Finance Minister Jim Flaherty said in an interview with CTV he's worried about people piling up debt while interest rates are low and then getting into trouble when interest rates rise, as they inevitably must.

Finance Minister Jim Flaherty says he worries about Canadians taking on too much debt. (CBC)

As a result, the Conservative government is considering increasing the minimum down payment from five per cent "to a higher figure," he said, and Ottawa may also reduce the amortization period from a maximum of 35 years "to something less."

Twenty-five-year mortgages used to be the norm, until lenders started making 30-, 35- and 40-year mortgages available to stimulate demand. In mid-2008, the Department of Finance moved to trim the maximum paydown period to 35 years and to require a minimum five per cent down payment for new federally insured mortgages.

Even so, 18 per cent of Canadian mortgages are for terms longer than 25 years, and 10 per cent are amortized over 35 or 40 years, a recent Scotiabank report estimated.

The average price of a resale home in Canada hit $337,231 in November, the Canadian Real Estate Association said last week. That's 19 per cent higher than the depressed levels of a year earlier.

Flaherty's comments echo Bank of Canada governor Mark Carney, who last week urged consumers to get their financial houses in order to prepare for when the central bank inevitably raises its key policy rate from its current emergency record low of 0.25 per cent.

Proceed with caution: CIBC

Word that Ottawa might step further into the red-hot real estate market had housing watchers buzzing Monday.

"You could basically shut down 25 per cent of the market," CIBC economist Benjamin Tal told CBC's The Lang and O'Leary Exchange. "It's going to be significant because we're talking about a lot of money that took advantage of those rates."

"What the Bank of Canada and Finance Department are saying is that people are abusing these rates, but they need to be careful not to risk this fragile recovery."

Though he admits more lending caution would be prudent, he advocates Ottawa be wary of anything as drastic as a hard cap of 30-year amortizations, or minimum 10 per cent down payments, for example.

"If you want to do it, do it in a gradual way that you do not kill housing [because] housing is the only thing ticking in this market," he said. "The timing is tricky."

With files from The Canadian Press