The personal details of thousands of Australians were leaked on Wednesday after a hacking attack on public broadcaster ABC in protest at an interview with far-right Dutch politician Geert Wilders.
The Australian Broadcasting Corporation (ABC) said it was investigating "reports of a security breach on an ABC site", with a Twitter user named @Phr0zenM claiming it was part of a hacking mission named #OpWilders.
"ABC hacked for giving a platform for Geert Wilders to spread hatred #OpWilders - database leaked!" @Phr0zenM said.
The details of some 50,000 Australians, including email addresses, usernames and passwords, addresses and other sensitive information, were reportedly posted online by the Twitter user, with victims said to include some 1,000 government employees.
An ABC spokeswoman told AFP the broadcaster had been "made aware that an ABC television programme website was hacked. The website relates to the ABC television programme Making Australia Happy, which aired in late 2010".
"At this stage, we are still investigating the details of the breach. However, we do know that it has exposed the name, username and a... version of the password that audience members used to register on the programme website," she said.
"As soon as the ABC was made aware of this activity the site was shut down."
She noted that the breach "originated at an overseas location and an activist had claimed responsibility for it."
"The ABC will be in contact with audience members who have been directly affected," she added.
Populist anti-Islamist Wilders gave the interview to the ABC's Lateline programme ahead of his speaking tour of Australia.
There were protests outside a number of his events, including one Melbourne where police had to break up scuffles.