By Dominic Giannini, Kat Wong and Sophia McCaughan in Canberra

Pro-Palestinian protesters have scaled Parliament House and unfurled banners against its facade, fuelling security concerns among politicians.

At least four protesters were removed from the building by around 11.45am on Thursday after climbing up and unfurling banners accusing Australia of complicity in “war crimes” and “genocide”.

“We declare to the Australian government we will continue to unmask and resist the US imperial, hegemonic and capitalist interests you devote yourself to,” one protester from the group Renegade Activists yelled from the rooftop.

“Australia continues to enable and commit war crimes as lackeys to our ‘great and powerful’ friends.”

Opposition home affairs spokesman James Paterson has called for an investigation into how the protesters were able to evade security measures to climb onto the roof at parliament.

“This is serious breach of the parliament’s security, the building was modified at great expense to prevent incursions like this,” he wrote on social media site X.

Deputy Prime Minister Richard Marles said he had confidence in the building’s security but urged Australians to consider the way they express their views.

“We live in a country where we cherish free speech, where it is important that people are able to engage in peaceful protest,” he told reporters in Canberra.

“There isn’t a place for engaging in protest which endangers others, there is no place for engaging in protest which defaces public institutions or public buildings.

“That kind of protest, which engages in vandalism, defacing public buildings, is disrespectful to every Australian.”

Parliament House is built into Capital Hill with a grassed roof, which according to the Parliamentary Education Office, allows people to “stand above” their elected representatives.

Jacob, a representative from the Renegade Activists, said this was a consideration in their protest.

“We’ve gone back to that original idea of being above the parliament and letting the politicians know,” he told AAP, without giving further personal details.

One of the banners stated “from the river to the sea, Palestine will be free”

The phrase has been condemned by the prime minister and coalition who claim it supports a one-state solution where Israel wouldn’t exist.

However, it has also been used by pro-Palestinian protesters and Labor senator Fatima Payman – who controversially used the phrase to defy the prime minister – to call for justice and freedom in occupied territories while still supporting a two state solution.

The West Australian was suspended from the Labor caucus after she crossed the floor to support a Greens motion on Palestinian statehood and vowed to do so again in the same circumstances.

There has been speculation she could announce she is leaving the Labor Party on Thursday.

Senator Payman has described feeling isolated from her fellow party members, raising questions over her future political career.

“She’s doing what she has been employed to do and that is represent the best interests and the aspirations of her constituents,” Jacob said.

“What the Labor Party is actually telling us is that they would prefer people to bulls*** about how they feel, than to speak the truth.”