Leaked videos of staff from Australia's conservative government performing sex acts in parliament, including one man performing a lewd act over a female MP's desk, left Scott Morrison's administration facing yet another major scandal yesterday. 

The prime minister -- already under pressure for his handling of sexual assault allegations including that a female government adviser was raped by a colleague -- called the behaviour "disgraceful" and "absolutely shameful".

The videos and photos, which had allegedly been shared in a group chat of coalition government staff before being leaked by a whistleblower, were first revealed by The Australian newspaper and Channel 10 late Monday.

The graphic images have prompted fresh outrage from female lawmakers and the Australian public, coming on the heels of the rape allegations that sparked mass nationwide protests.

The whistleblower, identified only as Tom, told the news outlets that government staffers and MPs often used a Parliament House prayer room to have sex, and alleged that sex workers had been brought into the building "for the pleasure of coalition MPs".

He also said a group of staffers routinely swapped explicit photos of themselves and he received so many he had "become immune to it".

One aide was immediately fired. Minister for Women Marise Payne said the revelations were "beyond disappointing" and highlighted the need for a government-ordered inquiry into parliament's workplace culture.

The fresh sexism revelations on Tuesday prompted Indigenous Senator Lidia Thorpe to disclose alleged sexual harassment by four male politicians since she took office just six months ago. Thorpe, a representative for the Greens party, told the Canberra Times the "brazen" harassment had included "suggestive" remarks and unwanted touching.

Tens of thousands of women this month joined "#March4Justice" rallies to protest sexual violence and gender inequality, calling for systemic change in politics and wider Australian society.