The New Yorker walks in between rows of identical desks sandwiched together inside a windowless room in a Bangkok office block, exhorting his charges to get on their phones, to sound confident and to always, always be angling for a close.

"I came to Thailand with $2,000 [#2,300] in my pocket and a lot of debts but now I'm loaded," Mike brags during his 15-minute crash course on how to sell currency futures with Southeast Asia Trading, an unlicensed broking house telephoning Australian and New Zealand households and businesses promising fantastic returns and tax savings.

Itinerants and knockabouts, lured by the promise of hefty commissions, stick to the telephone receivers like galley slaves, babbling reassurances to potential investors that they are from a reputable organisation, that investing offshore is not dangerous and - most importantly - they should not wait and think about it but invest before the markets open in the US.

One trader stops Mike on his walkabout to check the latest word on the euro against the dollar and he tells them Bloomberg is predicting it will rise to $1.07.

He looks closer at the photocopied report Mike is grasping in his hand and points out the figure is actually 107 yen against the euro.

Welcome to the fast and furious world of "boiler rooms", the home of the cold-calling trader.

Attractive for its low rent, a time zone that makes Australasia and Europe accessible, and lax regulations, Thailand has become a hub over the last two years for firms selling bogus shares and investments to foreign nationals through high-pressure telephone sales.

Another feature that has drawn these firms to Bangkok - many of which have leapfrogged from Florida to the Caribbean, on to the Philippines and now Thailand - is a large supply of English-speaking travellers, particularly from Britain and Ireland, keen to work a few months and pick up some extra cash.

Some "trading advisers" have earned up to $8,000 in commissions in a month.

One diplomatic source put the number of "boiler rooms" at 25 to 30, with some employing hundreds of people calling numbers picked out of phone books.

"We are talking at least tens of millions of dollars a year, maybe hundreds of millions disappearing," says Ms Megan Cassidy of the Australian Securities and Investment Commission.

She adds that a lack of resources, limited jurisdiction and the natural reluctance of defrauded investors to come forward combines to make it difficult for the regulator to pursue these operations.

Most cold-calling firms offer an initial placement offer of shares or start-up investment in a company soon to be listed when, as the caller repeatedly assures the would-be investor, the price will sky-rocket.

The company never goes public and/or share certificates are not distributed and, by the time the investor realises it is a con, the money has been transferred out of the overseas bank account to which the share order was telexed, often to banks in the Caribbean.

One group raided in Bangkok this week, the Brinton Group, has a long history in the game of cold-calling.

The organisation traces back to other houses previously operating in the Philippines and the Caribbean, and has been selling initial public offerings and sourcing venture capital for US companies and in Gary Player Direct, a company run by the famous golfer's son.

One group of Australian investors that invested in both the Brinton Group and Benson Dupont International lost around £125,000 sterling (#203,000) according to Australian authorities.

Southeast Asia Trading has moved office twice since it began operations some six months ago and changed its name from Foreign Currency International after being listed on the New Zealand Securities Commission website when investors there complained about not being able to get their money back.

But still they keep calling, typically small business owners with little or no experience in investment, who had expressed interest in receiving some information in the mail when contacted by a "marketing representative". That was most likely to have been a backpacker who had answered an advertisement for "English speakers wanted" in the Thai English language press and was working for $250 a week in a room with hundreds of others calling names out of a phone book.