The report, by Stamford, Conn-based Gartner Group, said a combination of inadequate law enforcement and growing opportunities for cyber-crime left the door open for the theft of millions of dollars.

The study also said the theft was likely to be completed a few dollars at a time, from millions of different accounts, meaning it would be difficult to detect.

"Converging technology trends are creating economies of scale that enable a new class of cyber-crimes aimed at mass victimization," Gartner Research Fellow Richard Hunter said in a statement on Friday.

The report said consumers should be extra careful to monitor all their financial transactions for unexplained withdrawals or fund transfers.It also advised they install a personal firewall on any computer that has Internet access and disable any peer-to-peer networking, such as music swapping, on any Internet connected machine.

-- Reuters