Reviews of two schemes by the Securities and Futures Commission last year concluded they appeared to be outside the scope of the Protection of Investors Ordinance. But a commission spokesman said each scheme had to be examined on its own terms.

The Consumer Council has not received any complaints, but in January a Belgian company, Ostrich Farming Corporation, went bust. About 2,700 people had paid up to GBP17,000 (HK$207,400) for birds that were worth only around GBP1,500.

There are at least three overseas ostrich investment companies with offices in Hong Kong, and many advertisers, mainly from Australia, have appealed for local investors in the past two years, offering returns of up to 40 per cent a year.

Global Ostrich Investments, one of the three companies in Hong Kong and one of the largest ostrich farm owners in Australia, has around 100 local investors with about $10 million invested in the scheme.

The firm's manager, Karen Chan Wai-yin, admitted there was risk.

She advised potential investors to check farm sizes. Responsible farmers run large farms, with 3,300 square metres for each pair of ostriches, she said.

'Investors should look on it as a middle to long-term investment with farm runners who have a well-established track record, because the birds live a long time,' she said.

Ostriches live to between 70 and 80 years. They become reproductive by age two and can produce 10 to 20 offspring each year for 20 to 40 years.

Most schemes offer a basic package with an up-front fee of between $100,000 and $160,000 for a pair or a trio of the birds, which includes upkeep, management and farming.