Notorious left-wing activist Sally Rugg has filed a lawsuit in the Federal Court against independent MP Monique Ryan and the Commonwealth government, alleging a breach of "General Protections" under the Fair Work Act.

Lawyers representing the activist are seeking an injunction on her termination, which they argue was a result of her refusal to work additional hours, deemed "unreasonable".

The lawyers are also seeking a declaration that Ryan and the Commonwealth violated the Fair Work Act by "engaging in hostile conduct" in response to Rugg's refusal to work additional hours.

Rugg, who was named the chief of staff only six months ago, remains employed by Ryan's parliamentary office during the legal dispute.

The MP has appointed former Greens advisor Nina O’Connor as her interim replacement. The Federal Court has ordered an interlocutory hearing for Friday, February 3.

In contrast to these allegations, Ryan had been a vocal advocate for improving the workplace culture in Parliament House. She joined her crossbench colleagues in pushing for a Parliamentary code of conduct as recommended in the Kate Jenkins review into the workplace culture in Parliament.

"Introducing a Parliamentary code of conduct as recommended by the Jenkins' report will be crucial in improving the workplace culture of Parliament House," Ryan said on Twitter in June.

The outcome of the lawsuit will provide insight into the working conditions and employment rights in Parliament House.