A police union president says courts need to send a clear message to anyone who attacks officers.
The video posted online appears to show a female officer being punched square in the face by the offender who was then tasered and apprehended by fellow officers.
The incident occurred at Great South Road, Manurewa about 12.17pm on Monday.
A police spokesperson said the officer involved was knocked unconscious and was now off work recovering.
One person has been arrested following the incident.
New Zealand Police Association president Chris Cahill said these types of assaults on officers were all too common.
"The violence is raw to witness and unfortunately assaults of this gravity are not rare, with more than 2000 assaults on officers last year alone."
He said being assaulted was not "just part of the job" of keeping communities safe.
"If police officers are not protected how are they supposed to protect New Zealanders?"
Cahill said the association would work with the police wellness team to support the officer.
"The callous unprovoked attack on the young female officer which was videoed by a member of the public reveals to New Zealanders the atrocious and unacceptable level of violence our members face on a daily basis."
Police Minister Chris Hipkins said the footage was a reminder of the difficult job the police did for communities every day.
"From the footage this looks like a nasty incident, and I know police will be supporting the officer involved. No officer should have to go through that."
A 27-year-old male appeared in Counties Manukau District Court today charged with intent to injure.