Hannah, a former Greens candidate who challenged the Australian prime minister at the elections in May, allegedly declined to comply with the order to disperse, the Guardian newspaper reported.

Police said she sustained facial injuries during the arrest and was taken to a hospital for treatment.

New South Wales Greens MP Sue Higginson said that Hannah was a “victim of brutal excessive force by the police”.

She said Hannah’s family had been told that the extent of her injuries could not be known until there was a full examination because the swelling was too severe and that it was possible “she may lose vision in that eye”.

“But nothing has been confirmed at this point in time,” Higginson was quoted as saying.

Images of Hannah making the rounds online show her right eye to be “badly swollen and bruised”.

Hannah was at a protest aimed at stopping pedestrian access to a business accused of supplying services for a variety of applications including aerospace and defence technology to Israel.

Hannah, who has been vocal in her support for Palestinians, was subsequently forcibly removed and arrested.

The authorities said the protest was unauthorised, as participants had not provided advanced notice nor submitted a form that protected them from being charged under anti-protest laws.