His women friends were cheating on their husbands but needed plausible excuses, so Raul Tello came up with a hi-tech solution: an internet site that provides all the excuses for a four-star affair.

As a web page designer Mr Tello had all the tools to provide an anonymous communications network that would allow for Argentina's lovers to make elaborate getaways.

"We design invitations to conferences, provide the airline tickets and send the invitation to the client," said Mr Tello, the founder of www.amorios.com.ar.

"After the conference they receive certificates of attendance and if necessary, invitations to a follow-up conference," he added.

Despite an economic slump that has hammered most small businesses in Argentina, the affair-planning business appears to be recession-proof. In the first 60 days, Mr Tello grossed £25,000 and signed up 300 clients.

For an annual fee of£40, the clients receive a coded card with their "identity" and an email password. The website has a complete package deal that can be used to convince not only the unsuspecting spouse but also the boss that the unfaithful party is away on business.

"We put a lot of effort into convincing the client's supervisor that this is a business trip," Mr Tello said.

However, Amorios.com is only capable of taking on 1,000 clients. The logistics of planning an affair in Argentina are particularly complicated because so many people suspect their partners of infidelity.

Cover trails are laid in elaborate detail. For example, should a suspicious spouse call the "conference", someone playing a secretary in the Amorio offices will grab the corresponding mobile telephone and read an appriopriate script. Background noise is then blasted over the office loudspeakers to simulate the atmosphere of a conference.

The caller is told that their spouse "just stepped out" and the lover is contacted and told to phone home straight away.

With more than a dozen phones spread out on the desk, the margin for error increases with the number of scripts, sound effect tapes and new personnel.

Mr Tello insists that there have been no major errors but some would argue it is only a matter of time before the wife of a doctor at the Mexican "engineering conference" is played the tape of the Brazilian nurses' association. "With Amorios, there will be no failures, we study every case thoroughly," Mr Tello said.

The clients of Amorios.com are equally divided between the sexes. "I don't care if it is women with women, men with men, whatever. People who are unfaithful will be so with or without Amorios, I am just providing an excuse, nothing more."

Due to the interest from other South American nations, Amorios.com hopes to expand into Uruguay and Peru. "We aren't sure whether to franchise this or do it ourselves, but the number of calls from Peru is huge," Mr Tello said.

But his biggest market may never be realised - in neighbouring Brazil extra-marital affairs are so common that excuses are often unnecessary.