He said he was grabbed by police immediately after a protester directly beside him tossed an officer aside.
The man, identified as Phil in the Facebook video, said he couldn't retreat when police punched him and gouged his eyes.
A police spokesperson said it was an extremely difficult working environment for frontline staff.
"However, police have been exercising their powers fairly and professionally, and have used force proportionate and relevant to the circumstances."
The spokesperson said images and videos often did not provide the full context of the protest activity and the situation police staff faced.
Police would not comment on individual arrests, the spokesperson said.
The man issued a message to other protesters saying "the cops are not our enemies" and urged them to remain peaceful.
He also revealed that Auckland socialite Gilda Kirkpatrick had gifted him a new phone, after claiming police "stole" his.
Kirkpatrick said Phil was a friend.
"He was in distress and pain so that was the least I could do," she told the Herald.