Djab Wurrung Gunnai Gunditjmara senator Lidia Thorpe was shoved to the ground by police while participating in a counter-protest on Thursday.
The Victorian senator was attacked after approaching a small rally being held outside federal parliament by British anti-trans commentator Kellie-Jay Keen-Minshull.
Ms Keen-Minshull was speaking to a group of protesters under a marquee in the rain when Senator Thorpe, carrying an the Aboriginal flag, crossed the street and attempted to enter under the marquee.
Video footage shows Senator Thorpe approach Ms Keen-Minshull and call out "you are not welcome" several times to the anti-trans agitator before being shoved by a man in a suit and then pulled to the ground by a uniformed police officer.
An as yet unidentified woman who was part of the anti-trans group also appears to be trying to grab Senator Thorpe.
The senator crawled away from the anti-trans protestors before getting to her feet and joining a counter-protest a short distance away.
Speaking to reporters after the incident, Senator Thorpe, referring to the anti-trans group, said "we do not tolerate this kind of filth on Ngunnawal Country".
She said the anti-trans movement is "destroying people's lives".
"This country should be ashamed that they even let people like this into this country," she said.
"I went to tell her… that they are not welcome here and I got pulverised by the police for simply telling this person they are not welcome here."
Senator Thorpe said the police should be held to account for "the assault", and that the government needs to be held to account for allowing Ms Keen-Minshull into Australia.
In a statement, the Australian Federal Police said the incident would be reviewed.
"The interactions between the AFP and protesters will be reviewed, and an incident has been referred to the AFP's Professional Standards Command," it said.
"Given a matter is now under investigation, no further comments will be made."
After the incident, Darumbal/South Sea researcher, academic and advocate Amy McQuire backed the senator.
"I support Lidia standing up for the rights of transwomen who have a right to live free of violence. The Nazis and the peddlers of hate speech are protected while Black women are brutalised," she wrote.
Writer Su Dharmapala noted: "If an Aboriginal Australian senator is treated like this in the full view of cameras, you can get a sense of the violence when there are no cameras."