The Police Association is warning crime could rise as administrative staff numbers fall.
It says more than 180 civilian staff were cut between December 2011 and December 2012.
Speaking at the association's annual conference on Wednesday, president Greg O'Connor warned that the police's organisational infrastructure was being dismantled by getting rid of so many staff.
He says New Zealanders should be very wary of police having to use untrained volunteers as substitutes for non-sworn staff, and although the practice may bring short-term savings, it will have long-term consequences.
Mr O'Connor says while the Government claims it is committed to improving frontline policing, job cuts are forcing those police to take on more backroom responsibilities.
But Police Minister Anne Tolley says there is no evidence that fewer non-sworn staff will have an impact on the falling crime rate.