The Canadian investor Arthur Wong is buying condos in Las Vegas and Phoenix like a shopper at a discount retailer: in bulk, with slashed prices.

Mr. Wong, president of Optimus U.S. Real Estate Fund, has bought 60 condos at heavy discounts from developers in financial trouble. He paid about $62,500 each for 18 Las Vegas condos that once were priced at about $250,000 apiece.

‘‘This could be a once-in-a-generation opportunity for real estate investment,’’ said Mr. Wong, whose fund, based in Calgary, Alberta, has already invested $5 million cash and will spend millions more in the U.S. Southwest over the next several months.

While investment in U.S. real estate from abroad in the first six months of 2009 was lower than the level last year, real estate agents from NewYork to Las Vegas say purchases have increased rapidly in recent months.

Foreign investors have long been attracted to U.S. residential real estate, drawn by the market’s stability compared with other countries. But the dollar’s descent in the past six months makes homes even cheaper for foreigners, and prices are growing more stable.

International investors bought 154,000 homes and condos in the 12- month period ending in May, down nearly 10 percent from 170,000 for the same period a year earlier, the National Association of Realtors reports.

But since June, the dollar has tumbled by 9 to 11 percent against currencies like the yen, the euro and the Canadian dollar.

The Brazilian real has gained 17 percent against the dollar in the past six months.

Buyers from Brazil, Canada, France and the Netherlands, for example, have paid mostly cash for second homes ranging from $6 million to $15.5 million in condo buildings like 40 East 66th Street in New York City.

Cynthia Crowley, a real estate agent in New York, recently spoke with three different Israeli investors who have complained about rising real estate prices at home.

‘‘They want to buy,’’ said Ms. Crowley, an agent with Olshan Realty inManhattan.

‘‘This is not tire kicking.’’ Foreign investors love floor-level prices and the limp dollar but also are confident in a long-term recovery of the U.S. economy and the housing market’s resurgence. Some want vacation homes, while others are looking for rental income.

Buyers from Canada, India, the Middle East, Mexico and Venezuela like Houston’s neighborhoods and its economy, which benefits from strong oil and health care industries.

‘‘They also like to gravitate to where they have friends or family,’’ said Bill Gottfried, managing director of Gottfried International Estates.

Foreign investors often pay cash, or offer down payments of 40 percent or more, because financing is difficult to get. Nearly half paid cash in the 12- month period ending in May, the Realtors group reports.

Florida leads the United States in the number of international buyers, accounting for nearly a quarter of foreign purchases. It was followed by three other states with warm climates—California, Texas and Arizona.

Miami home prices are down by half from the peak period of late 2006 due to foreclosure sales and a glut of unsold units. With the dollar hitting a 15-month low this week against the euro, the bargains are enticing. Investors are buying single-family homes or condos for twothirds the cost three years ago.

Peter Zalewski, a real estate agent based in Miami, said at least seven bulk deals involving foreign condo buyers have taken place in downtown Miami alone, with investors coming from Argentina, Canada, Colombia, Italy, Norway and Venezuela. Similar deals also have taken place in the heavily populated Broward County and in thewealthy Palm Beach County, both north of Miami.

Claudia Bacelar, a real estate agent with Esslinger Wooten Maxwell, has seen more South Florida inquiries from Brazilian, Canadian and British buyers of second homes, many of whom gravitate to condos in the $800,000 range. And they pay cash.

Marco Bordoni, a native of Argentina, bought an $860,000 house in the Golden Isles area of Broward County last month. He is spending $450,000 to remodel the house, which was valued at $1.2 million four years ago, said his agent, Scott Patterson.