TORONTO — A sliver of land wedged between Toronto’s elevated expressway and an off-ramp that pumps traffic into downtown may become the epicenter for a Canadian housing bubble.

In four years, this site that’s now used as a parking lot and police impound near the shores of Lake Ontario will be home to Ten York, a 75-story glass building that would be the country’s third-tallest condo tower.

Toronto has more skyscrapers and high-rises under construction than any North American city — almost three times as many as New York — stoking debate on whether the condominium market in Canada’s largest city is headed for a U.S.-style correction as prices rise and household borrowing hits a record. Canadian lenders including Toronto-Dominion Bank last week raised mortgage rates to cool off the housing market.

“Condo construction has always been rather prone to boom and bust cycles, and this one seems particularly strong,” said Sheryl King, an economist with Bank of America Merrill Lynch in Toronto. “Builders seem to overestimate how much demand is going to be out there, and that’s when you tend to see some abrupt pull-back.”

Canada’s housing market is about 10 percent overvalued, with inflated prices primarily in Vancouver, Montreal and Toronto, King said in a telephone interview. “We would call it a bubble,” she said.

Rising home prices have led to a 53 percent increase in residential mortgage credit in the past five years, or an average rate of 8.9 percent a year. The volume of outstanding mortgages rose to C$1.08 trillion ($1.08 trillion) as of August, according to the Canadian Association of Accredited Mortgage Professionals. Defaults remain low, at 0.42 percent, according to data from Canada Mortgage & Housing Corp., a government-run housing agency.

The country’s financial authorities have become increasingly vocal about the housing market. The heads of Bank of Montreal and Royal Bank of Canada; the country’s banking regulator, and Bank of Canada Governor Mark Carney have all expressed concerns about the condo markets in recent months as cranes and construction crews swamp Toronto.

Toronto has 148 high-rises and skyscrapers being built, compared with 59 tall buildings for No. 2-ranked New York City, and 22 in Chicago, according to Emporis, a Hamburg-based building data company.

Most of the work is for housing, with 105 residential high- rises proposed or under construction, according to a database by Fourteen are slated to finish this year, including two hotel-condos. Trump International Hotel & Tower Toronto, Canada’s tallest residential building, opened Jan. 31, adding 118 luxury residences to the city’s inventory.

“The number of units under construction is quite high, start levels have trended up, and the number of units coming to completion is growing,” said Shaun Hildebrand, a senior market analyst for the Greater Toronto Area with Canada Mortgage & Housing Corp. “Supply at all ends of the development process is growing quite quickly.”

A record 27,504 condo units in the City of Toronto were under construction at the end of last year, according to Canadian Mortgage & Housing annual data, adding to the city’s total of 199,000 units.

“If builders stopped building today, there’s five years worth of supply that is about to be delivered, relative to what normal population growth is,” Bank of America’s King said.

Investors are piling into Toronto’s condo market because of cheap borrowing costs and that may become risky when interest rates rise, said John Andrew, a real estate professor at Queen’s University in Kingston, Ontario.

“They’re being bought because the interest rate is very low,” Andrew said in a telephone interview. “They’re financed to the hilt, so they’re very sensitive to the refinance risk when the loans come up.”

Banks are also cutting their funding costs by selling covered bonds, a form of corporate bond backed by assets such as home loans. Bank of Montreal and Bank of Nova Scotia sold $4.5 billion of the securities last month, after a record $25 billion of sales in 2011. Relative yields on the covered bonds fell to 130 basis points on Feb. 9, down from 170 at the start of the year, according to Bank of America Merrill Lynch data.

The Bank of Canada has held its benchmark lending rate at 1 percent since September 2010 and will probably maintain that level until the second quarter of 2013, according to median forecasts from economists compiled by Bloomberg. Carney has said “excesses may exist in certain areas” of Canada’s housing market.

“The elevated levels of ‘multiples’ inventories, the ample pipeline of developments underway, and heavy investor demand (much of it foreign) reinforces the possibility of an overshoot in the condo market in some major cities,” Carney said in a June 15 speech in Vancouver.

Investors are underestimating the potential impact of the surge in condo supply coming onto the market in the next 12 to 24 months, according to King. That could drive down resale prices and rents, even with low interest rates and a stable mortgage funding market.

“Investors are a concern given rental rates no longer fully cover costs and unit price increases going forward will not likely provide sufficient return,” the Office of the Superintendent of Financial Institutions said in a June draft report obtained last month by Bloomberg News through an Access to Information request.

Foreign buyers are also affecting housing, according to OSFI. The bank regulator has been monitoring the impact of foreign investment on the housing markets in Toronto and Vancouver, the documents obtained by Bloomberg show. Authorities in China, Hong Kong and Australia have recently taken measures to cool off their residential real-estate markets, the documents note.

“The stability of Canada has moved it to the forefront of investor preference, in some cases ahead of the U.S.,” states a draft analysis of Toronto’s condo market.

Investors represent a “significant portion” of Toronto’s condo market, with 20 percent to 30 percent or higher for some projects, the report said.

High-rise homes reached a record 62 percent of all new home sales last year as condos outsold traditional detached homes three to one, RealNet said in a Jan. 20 report with the Building Industry and Land Development Association. That’s up from 25 percent of the market in 2000.

“In absence of another recession, we’re not expecting demand to fall,” Canadian Mortgage’s Hildebrand said. “We’re expecting it to hold steady so long as the economy holds steady.”

Toronto is home to about 2.5 million people — more than double that including its suburbs — and accounts for about 11 percent of Canada’s economic output, according to the City of Toronto. The city is home to Canada’s five-biggest banks, two of the three largest Canadian insurers as well as some of the country’s largest pension funds, asset managers and financial- services firms.

Realtors and others in the industry say the record condo units under construction will be easily absorbed by 100,000 immigrants streaming into the city each year, wealthy foreign investors looking for a haven to park their money and young urbanites demanding to work near the financial industry that is the backbone of the city’s economy.

“There are reasons why people want to spend time in Toronto, and that’s part of what supports these real-estate markets,” said William Strange, RioCan Real Estate Investment Trust Professor of Real Estate and Urban Economics at Rotman School of Management in Toronto. “Toronto tends to be a pretty good place to do business and, with respect to Canada, it also tends to be a place where people want to live.”

Tridel, Toronto’s biggest condo developer, is already fielding calls for the 783 units of Ten York and plans to start selling in April, more than a year before the C$295 million project begins construction.

“There’s a tremendous amount of interest,” said Jim Ritchie, senior vice president of sales and marketing for Tridel. “We have thousands of names of people who want to buy here.”

Developers sell most units of a project before building begins, and many investors buy the condos to either resell or rent out when the construction is finished. Rental units accounted for 24 percent of all condos in Toronto last year, up from 21 percent in 2010, according to CMHC.

Fallout from Toronto’s construction boom may not surface immediately, according to Queen’s University’s Andrew.

“It’s going to be three-and-a-half to four years from now when these loans are all coming up and you’ve got a number of people who say they can’t afford to refinance it, so they’ll just sell,” Andrew said. “They’ll find out that 40 units in the building all went on the market in the same month, and now they’ve got a big problem.”

— With assistance from Andrew Mayeda, Ilan Kolet and Theophilos Argitis in Ottawa and Sean B. Pasternak in Toronto.