The Prime Minister's website has been hacked in protest over a federal government proposal to introduce a mandatory filter to censor internet content.

The pm.gov.au website was brought down at about 7.20 (AEST) last night along with that of the Australian Communications and Media Authority.

There was also an apparent attempt to bring down the website of the Communications Minister, Stephen Conroy.

A check confirmed the PM's website was down at 8pm.