Hawks spokesman Brigadier Hangwani Mulaudzi said that its cyber crimes unit was flooded with reports of the computers of big businesses being hijacked, and of syndicates using jobless people and bank employees to siphon off money.

"Syndicates take over the server of a company and then demand a ransom [to restore control to the company]," he said.

"Cyber crime is severe and we often assist [other countries] through Interpol.

"If need be, we go abroad and testify. We have a mutual understanding between the countries as to how we deal with the suspects."

Mulaudzi did not give figures or examples, but said there were several cases of cyber-related crimes in the courts.

He spoke after Interpol nabbed a man known only as "Mike", said to be a 40-year-old Nigerian linked to an international online syndicate behind the theft of $60-million.

Its victims are reportedly all over the world, including South Africa. One victim is believed to have been conned out of $15.4-million.

Mike's network allegedly hacked the e-mail accounts of small businesses in countries including Australia, Canada, the US and South Africa. Interpol said that, through compromised e-mail accounts, it preyed on the businesses' clients and suppliers.

Investigators found that the syndicate involved at least 40 people in various countries.

"The main types of [scam] run by Mike were payment-diversion fraud, in which the supplier's e-mail would be compromised and fake messages sent to the buyer with instructions for payment to a bank account under the criminals' control," said Interpol.

Examination of devices seized by the Nigerian Economic and Financial Crime Commission showed that "Mike" was involved in many criminal activities, including "romance scams".

He faces charges such as hacking and conspiracy to obtaining money under false pretences.