A group of suspected internet racketeers, who fooled people into sending them money by pretending to be from the central bank of South Africa, have been arrested.

A spokesman for South Africa's elite criminal investigations unit - known as the Scorpions - said 15 Nigerians had been detained, and would appear in court on Monday.

He said the gang, operating via email, promised to pay its victims a commission for looking after $10m, and directed them to a website which looked similar to that of the South African Central Bank.

The fictitious website then asked for advance payments to cover insurance and other costs.

When money was paid, it was never seen again.

Fast growing

Gerhald Nell, spokesman for the Scorpions said: "The web site gave the scheme legitimacy."

He said the gang diverted phone calls and created fictitious email addresses to fool people.

Nigerian money offer's like this have been described as the fastest-growing type of internet fraud.

Reports of e-mailed Nigerian money scams - designed to obtain recipients' bank account details by offering to transfer large sums to them for safekeeping - rose by 900% between 2000 and 2001, the NCL, the main US consumer lobby, have said.

Scams of this kind, which often emanate from Nigeria or other African countries, have been circulating for years through the post or by fax.