VANCOUVER - Wealthy foreigners hoping to fast-track immigration to Canada are preparing to sue Ottawa over the government's cancellation of its immigrant investor program, which has been assailed for allowing rich Chinese to buy their way into Canada.

Timothy Leahy, a lawyer who represents a group of mostly Chinese would-be immigrants in an ongoing case over long wait times for the now-defunct program, said he expects to file a second lawsuit within two months. This time, he and fellow immigration lawyer Rocco Galati are eyeing class action.

"We're going to try to start a so-called class action for the investors whose files were closed," Leahy said. "If closing down the files is struck down as illegal, it would apply to everybody."

That would mean the revival of thousands of applications that were killed when the Conservative government's Bill C-31 passed through parliament in June. The legislation cancels the "millionaire" immigration stream for which some processing times had lengthened to more than five years.

Canada's Federal Court ruled against Leahy's group of would-be immigrant-investors on the wait times case in June, though Leahy has filed an appeal that he expects to be heard sometime next year. The new lawsuit would be a separate case challenging the cancellation of the program

Launched in the mid-1980s, the immigrant investor program promised a fast-track visa for foreigners who had a minimum net worth of $800,000 and at least $400,000 to invest in the country. The minimums were later upped to a net worth of $1.6 million and $800,000 to invest.

Nancy Caron, spokeswoman for the government's citizenship and immigration department, said the backlog of investor applications was bogging down the immigration system. She said that with its cancellation, the government can now focus on initiatives that will better meet the country's economic needs.

Canada receives about 257,000 immigrants each year.

The program was wildly popular, particularly with ethnic Chinese investors - first from Hong Kong and Taiwan, and later from mainland China. Vancouver, with its proximity to the Asia-Pacific region, was the preferred destination.

"Many of my clients bought properties in Canada after they got the visa, but some of them bought before getting the visa," said Art Yang, chairman of Gasheng Overseas Investment Group, based in Guangzhou, China.

"They would be the more radical plaintiffs in this case against the federal government because they feel that they had spent a lot for the immigration."

Nearly 30,000 Chinese landed in Vancouver in the 1980s and 1990s on investor-class visas, according to data compiled by David Ley, a Vancouver-based geographer and author of the book "Millionaire Migrants".

"This was all quite deliberate," said Ley, who is also a professor at the University of British Columbia. "Basically, the three levels of Canadian government here - city, province and federal - were very eager to get investment from East Asia."

But the program may have been too successful. In the 2000s, Chinese applications soared, hitting a peak in 2010. By 2012, the backlog of unprocessed applications in Hong Kong alone hit 16,340, up from just 1,645 in 2006, according to court documents. Each applicant may represent numerous dependants.

At the same time, housing prices were soaring in Vancouver, earning it the dubious title of North America's least affordable city and spurring a backlash against foreign investors for pricing ordinary Canadians out of the housing market.

After the cancellation of the investor immigrant program, realtors and developers braced for a collapse of Vancouver's luxury housing market, but so far that has not happened.

"We have not seen any measurable impact on Chinese demand for property in Canada as a result of the ending of the investment visa program," said Andrew Taylor, co-CEO of Juwai.com, an online marketplace that helps Chinese people to invest in overseas real estate. "Canada is still a top-five country for Chinese buyers.

"The music will keep playing as long as Canada is willing and China is wealthy."