Five people were arrested while protesting Israel's war in Gaza outside an Australian firm linked to the manufacturing of fighter jets used by the IDF.
Hannah Thomas, 35, who was the Greens candidate for Prime Minister Anthony Albanese's seat of Grayndler, was taken to hospital with facial injuries suffered in the process of her arrest.
A photo of Ms Thomas in an ambulance shows her eye swollen shut and with blood on her face before she was taken for surgery.
Video of the incident shows multiple police dragging one of the protesters as on-lookers repeatedly shouted "get off her" and "let go of her".
Police said matters escalated after officers issued a move-on direction to a group of 60 protesters who had blocked pedestrian access to SEC Plating in Belmore in Sydney's southwest early Friday morning.
They said Ms Thomas was arrested for not complying with that direction.
NSW Greens MP Sue Higginson labelled the policing "excessive" and "unnecessary" and called for an investigation "to avoid further horrific instances of innocent people being seriously injured".
She has written to Police Minister Yasmin Catley, the NSW police commissioner and the state's police watchdog demanding the investigation.
"Having witnessed the grievous injuries caused by the police to Hannah Thomas, spoken to on ground witnesses who witnessed what occurred, and with the knowledge that Hannah has experienced serious injuries and hospitalisation, I am calling for a critical incident to be declared urgently," Ms Higginson wrote in her letter.
A police statement said the medical advice they had received about the incident did not meet the threshold for a critical incident declaration.
"Should further medical advice be received, the decision can be reviewed," it said.
Protest organisers say another protester was grabbed by the neck and choked, while others were knocked to the ground.
SEC Plating is reportedly providing plating services for various parts used in F-35 jets, of which the Israeli military has about 40.Â
Zack Schofield, a 26-year-old Rising Tide organiser who was arrested, said he was "objecting to genocide and the complicity of Australia in this".
"The excessive force used by police was brutal and will be put into question," he said.
Greens Senator Mehreen Faruqi said Ms Thomas had been a "tireless advocate" for the tens of thousands of people killed in Palestine.
"Hannah has long been a fearless and strong advocate for the rights of all people to live without oppression and occupation ... I am in awe of her courage and conviction in supporting people who need help," she said.
The five arrested protesters were granted bail to appear in Bankstown Local Court on July 15.