Green Party co-leader Marama Davidson receiving medical treatment after being struck by motorcyclist at Posie Parker rally

Green Party co-leader Marama Davidson is receiving medical treatment after being struck by a motorcycle in Auckland on Saturday amid the chaos that unfolded at anti-transgender activist Posie Parker's rally.

The incident has been reported to the police, Davidson's fellow Greens co-leader James Shaw said in a statement. It unfolded after the motorcyclist apparently failed to stop for Davidson at a pedestrian crossing, Shaw alleged.

Shaw said Davidson had been in attendance at the rally "in support of trans and non-binary human rights in Tāmaki Makaurau Auckland".

Davidson had stepped onto a Princes St pedestrian crossing when bikes kept racing past her, The Spinoff reported citing footage of the incident. One of the bikes appeared to then hit Davidson, forcing her back to the footpath holding her stomach - where the bike's handlebars had struck her, The Spinoff said.

Shaw said Davidson was seeing a doctor and the incident had been reported to police.

"The Green Party's commitment to non-violence is at the heart of our founding values. This news is upsetting and we are asking people to show care and love."

Newshub has contacted the police for comment.

In an update, the Green Party said Davidson was now resting at home with whānau.

"We stand with our trans and non-binary whānau and we stand with our co-leader. Our commitment to inclusivity and non-violence is stronger than ever," they tweeted.

Earlier on Saturday, chaos erupted as supporters and counter-protesters gathered at Auckland's Albert Park for Parker's rally.

Newshub reporter Nick Truebridge, who was at the scene, said the rally was "absolute chaos".

Some sort of substance - probably tomato sauce or paint - was thrown at Parker as she arrived, Truebridge said. 

Footage then emerged of scuffles breaking out as Parker was evacuated by security guards. Truebridge said the scene was "riotous".

As soon as there was a safety risk to Parker, "she was escorted from the area by police staff", a police spokesperson said earlier.