The Web site of the Sydney landmark has been found to harbour malware but it has been described as an "irritant" rather than a "major security risk".
The Web site of Sydney's iconic Opera House joins the long list of 'trusted' Web sites to fall victim to hackers.
Internal monitoring by the Opera House discovered the Web site had been distributing a trojan to visitors using vulnerable browsers.
A spokesperson for the Opera House said that the trojan affected the site between 28 and 31 May, although the company has not received any complaints about the malware.
"The trojan was identified as low risk, so based on that information we decided to keep the site live. It was never a major security risk, more of an irritant," the spokesperson said.
The incident has been reported to the local police.
The Opera House is just one of a number of big name sites to be used as a platform to launch malware attacks. A recent Google security study revealed that a significant number of Web sites could be harbouring nasties.
Research from the search giant into over 4.5 million Web sites found ten percent were capable of launching a "drive-by-download" -- such as a trojan -- onto a user's PC.
With 70 percent of sites that have been compromised with malware previously considered "legitimate", security experts are concerned that restricting Web usage to trusted sites may no longer be enough to protect users from malware.