Pro-Palestinian protesters have breached security at Australia’s Parliament House to unfurl banners from the roof as a senator quit the government over its direction on the Gaza war.

Tensions over Israel’s war against Hamas dominated parliament’s final sitting day before a five-week break.

The four protesters were arrested after draping the words “war crimes” and “genocide” as well as the Palestinian rallying cry “from the river to the sea, Palestine will be free” for more than an hour over the building’s facade known as the Great Verandah.

Inside the building, Afghanistan-born senator Fatima Payman, the only Australian federal legislator ever to wear a hijab during sittings, announced she had quit the ruling Labour Party over her refusal to toe the party line on Gaza.

Ms Payman told reporters: “My family did not flee from a war-torn country to come here as refugees for me to remain silent when I see atrocities inflicted on innocent people.

“Witnessing our government’s indifference to the greatest injustice of our times makes me question the direction the party is taking.”

The first-term senator defied her government colleagues last week by supporting a minor party’s motion that demanded the senate “recognise the state of Palestine”.

Australia does not recognise a Palestinian state. The government is committed to a two-state solution in which Israel and a future Palestinian state can coexist, in peace and security, within internationally recognised borders, the policy states.

Ms Payman will remain in the senate as an independent. She is the first government legislator to leave since Prime Minister Anthony Albanese’s administration was elected in 2022.

Police said the four protesters are expected to be charged with trespassing.

They have been banned from Parliament House for two years, a police statement said.

The protesters triggered a security crackdown in Parliament House that prevented many members of the public entering the building. The public galleries of both the House of Representatives and the Senate were kept empty as a precaution.

House speaker Milton Dick said he was “deeply concerned” by the protests and had ordered an upgrade of security. Police were investigating how the protesters gained access to a secure area.

Mr Albanese told parliament he condemned the protest.

“Peaceful protest has an important place in our society, but this was not a peaceful protest,” he said.

“These actions have done absolutely nothing to advance any cause. Indeed, they have hurt the cause that those engaged in this reckless activity believe they are advancing.”