Thousands of Aussies may be hit by potentially lethal computer malware, it they dont act now.

That’s according to Communications watchdog, ACMA, who issued a warning about DNSChanger – malicious software, or malware as it is known, that may have been installed on your computer without knowledge.

Approximately 10,000 Australian internet users are currently infected with this malware, Australian Communications and Media Authority warned today.

If your computer is infected you need to remove it immediately or else risk Internet blackout by 9 July 2012, at which date you will be unable to connect to the web.

This is because the temporary solution to this malware developed by Internet Systems Consortium (ISC) is due to expire on July 9.

DNSChanger is a class of malicious software (malware) that changes a user’s Domain Name System (DNS) settings, enabling criminals to direct unsuspecting web users to fraudulent websites and interfere with their web browsing.

It has been associated with ‘click fraud’, the installation of additional malware and other malicious activities.

In November 2011, the FBI closed down a ring of cyber-criminals believed to be responsible for the worldwide spread of DNSChanger.

An estimated four million users were affected worldwide.

Head to ACMA’s diagnostic website that shows you whether or not you are infected with DNSChanger.

The site was developed by ACMA, CERTAustralia – the government’s computer emergency response team – and the Department of Broadband.

If you are infected, it provides links to tools and detailed documentation that may help you remove the malware.