He said police were making inquiries and searching for the offender, believed to be a 38-year-old Masterton man.
No one else was significantly injured in the attack.
This comes just two weeks after a woman was repeatedly beaten on a South Auckland street while her screams for help were ignored.
Praveet Singh, 40, was viciously attacked by a stranger on her daily walk, while people stood by and watched. No one intervened, despite her desperate pleas for help.
Mr Glassey said people need to consider their own safety before attempting to assist someone being assaulted.
"We don't want to end up with two or three victims when there could have just been one.
"If people are called upon to assist and they don't feel comfortable to do that, which is a judgment that they make at the time, and they can't be criticised for ... use 111 and try and remain in the area to be able to tell police exactly what has happened," he said. Additional reporting APNZ