A teary Fatima Payman has vowed to work through death threats and anger from Labor colleagues to push for Palestinian rights after she quit the party.
Senator Payman said she was "deeply torn" but had been left with no choice because she believed Labor was moving too slowly to recognise Palestinian statehood and had exhausted internal options.
"Witnessing our government's indifference to the greatest injustice of our times makes me question the direction the party's taking," she told reporters during an emotional press conference.
About 38,000 people have been killed in Israel's counteroffensive in the Gaza Strip since October 7 after designated terrorist group Hamas killed 1200 people and took another 250 hostage, according to the local health ministry and Israel.
The war has sparked protests calling for a ceasefire and led to sometimes inflamed community tensions, with politicians calling for calm over the decades-long conflict.
The Labor Party had not been faithful to its tradition of championing the rights of all when it came to the war in Gaza, said Senator Payman, whose family arrived in Australia as refugees from war-torn Afghanistan.
"It's a crisis that pierces the heart and soul, calling us to action with a sense of urgency and moral clarity," she said.
"We have all seen the bloodied images of young children losing limbs, being amputated without anaesthetics and starving as Israel continues its onslaught.
"As a representative of the diverse and vibrant communities of Western Australia, I'm compelled ... to be their true voice in this chamber, especially when their cries for justice and humanity echo so loudly."
Senator Payman said she had private conversations with the prime minister, deputy prime minister, foreign minister and colleagues about recognising Palestine but got nowhere and was left with no other option.
Saying she resigned with a "heavy heart but a clear conscience", Senator Payman revealed she had received death threats in recent weeks.
She said she had been pressured by Prime Minister Anthony Albanese in a meeting on Sunday to either toe the party line or give back the Senate spot, but said his behaviour had not been intimidating.
She revealed colleagues had iced her out by not wanting to sit with her in the chamber and claimed some had stood over her.
Labor national president Wayne Swan said unity mattered and the West Australian's decision to put herself outside the party tent empowered their opponents.
Labor had consistently supported a two-state solution, he said.
But supporting a two-state solution while one isn't recognised was counterintuitive, Senator Payman said.
"This needs to happen in order to continue putting pressure on Israel to cease its onslaught," she said.
Greens leader Adam Bandt branded the senator's action courageous while the opposition attacked the prime minister's leadership.
Foreign Minister Penny Wong said she had reached out to check on Senator Payman's welfare and mentioned a parliamentary support service was in place to make complaints about any bullying allegations.
Labor members have also said they had tried to reach out to the West Australian to no avail.
Silent and expressionless, Senator Payman sat through part of question time on the crossbench on Thursday.
The senator then walked out of the chamber as Nationals frontbencher Bridget McKenzie was chastised by the Greens for her line of questioning.
"So much for the sisterhood," Greens senator Sarah Hanson-Young interjected.
Senator Payman has also been accused of making a political play after she admitted to meeting with a political strategist set up by a grassroots Muslim community group expected to target Labor seats.
The prime minister insinuated on Wednesday something had been in the works for over a month.
"It's not true," Senator Payman said, denying any affiliation or plans to join other political parties.
