The Police Association says it is a matter of time before an assault on an officer results in a death.
In the latest incident a 50-year-old policeman was attacked by two people in the Auckland suburb of Glen Eden overnight on Thursday.
The sergeant suffered bruising, cuts and a hand injury when he was attacked as he responded to reports of a domestic dispute at a boarding house.
The police union's president, Greg O'Connor, says barely a week goes by without an attack on an officer.
"More of our officers, particularly those who are working alone, are being assaulted seriously. And it's not the young officers who perhaps might not be expected to see the risk coming - these are older NCOs or sergeants that are being assaulted."
This month, a constable in Auckland was stabbed in the face, and in September, a sergeant was attacked from behind, then punched, kicked and stomped on.
Mr O'Connor says this week's week's Police Association conference will look at ways to reduce the risk to officers, particularly those working alone.
