In a note posted on its support site in late November, Apple said it wanted to "encourage" people to use anti-virus to stay safe online.
The move is widely seen as a response to the growing trend among cyber criminals of booby-trapping webpages that can catch out Mac users.
Before now Mac users have been largely free of the security problems that plague Microsoft's Windows.
....in recent months, hi-tech criminals have signalled a change in tactics away from e-mail borne viruses. Instead, many are infiltrating popular webpages in a bid to infect the machine of any and every visitor.
Many seek to steal valuable information such as login names, passwords or game accounts instead of trying to install themselves on a machine.