Witnesses say there has been a big brawl involving illegal car window washers in Auckland, after a driver objected to his window being washed.

Manukau Central Business Association general manager Kerry Burridge said the incident happened by the intersection of Cavendish Drive and Great South Road about 1pm today.

Things escalated when a man got out of his car and was attacked, she said.

"A large brawl developed across the whole intersection with the window washers that spread into the adjacent mall," she said.

"One of our directors tried to intervene, who was at the intersection, and help the chap from the car, who was being assaulted."

Ms Burridge said her colleague's motorbike was stolen while he was trying to help.

Stephen Grey, a member of the Otara-Papatoetoe Local Board, said he also saw the attack and tried to intervene.

"They chased this all round the place. They were inside the shop, the gas station shop.

"The staff at the gas station rung the police and when the police arrived, when they heard the sirens, they left the scene," he said.

There was a lot of blood, and the driver was left bleeding from his head and mouth, he said.

The police said the disorder was over by the time they arrived.

In a statement, an Auckland Council spokesperson said today's incident showed that although window washing was not allowed to be carried out in an intimidating way, it continued to be an ongoing issue in parts of Auckland.

The council said it received about 40 complaints on average per month about window washing.