The bank at the centre of the alleged fraud collapsed in 2001

They allegedly persuaded a senior bank official to send the money for what they claimed to be a new airport in exchange for a $10m (�5.4m) commission.

Correspondents say Nigeria has gained global notoriety for such scams, in which people are promised vast wealth for their help in dubious schemes.

Nigeria's anti-graft agency says this trial shows it is fighting such fraud.

Abuja's high court is due to hear how five Nigerians in total duped the head of international finance at Banco Noroeste in Sao Paolo, Brazil.

They are accused of telling the bank official of the huge personal commission he would get in return for investing up front in the Nigerian airport contract.

The Brazilian worker allegedly dug illegally into his bank's funds and transferred $242m in a series of payments to accounts around the world.

'Global network'

Nuhu Ribadu, head of Nigeria's Economic and Financial Crimes Commission, said the swindle took place over a four-year period starting in 1995.

The discovery of the scam has led to criminal investigations in Switzerland, Britain, the United States and Brazil, said Mr Ribadu.

A feature of the case is "the truly global network of fraudulent individuals" involved, he said.

Such advance-fee frauds are also known as "419 scams" - named after the section of the West African country's criminal code that prohibits fraud.

It involves scam artists - often masquerading as corrupt officials or sons and daughters of dead dictators - offering people via e-mail or faxes shares in hidden fortunes in exchange for simple administrative assistance.

Victims are then tricked into handing over their bank account details, or paying out on never-ending "service charges".