A competition to infect an Apple computer running OS X with a virus has been halted following complaints from Apple users and fears of legal action.

DVForge, a digital video accessories company, was offering a $25,000 prize to anyone who successfully infected one of two PowerMac G5s it had set up for the purpose. The G5s were running OS X 10.3 Panther in a stock configuration without virus scanning software or firewalls. The competition was in response to recent statements by anti-virus vendor Symantec, claiming that Apple’s OS would be under increasing threat from viruses.

Jack Campbell, chief executive at DVForge, said: “I have taken the difficult decision to cancel our contest. I have been convinced that there may be legal issues stemming from such a contest, beyond those determined by our own legal counsel prior to announcing the contest.”

No viruses targeting Mac OS X have yet been found in the wild.