A criminal defence lawyer has issued a warning about arming police after a call by Police Association members for sworn officers to carry guns.

Photo: SUPPLIED

Police Association members voted unanimously in favour of arming sworn officers at their annual conference on Thursday and have called on the Police Commissioner to start the process of arming officers.

But the lawyer Marie Dyhrberg has warned that if all police were armed, more criminals will start carrying guns.

She has campaigned for years against officers carrying tasers and is on a consultative body with the police on the use of force.

Ms Dyhrberg said if criminals know they will face officers with guns they will be more inclined to arm themselves.

"In my view it's going to increase the danger and ultimate safety of police officers and members of the public if all officers and frontline are going to be armed because the natural response to that is going to be the criminals are going to be armed as well."

Marie Dyhrberg says police officers she has spoken to are against being armed.

Commissioner not in favour

The Police Commissioner said calls from the Police Association to arm all officers are not backed up by evidence which shows assaults on staff are falling, along with crime.

Commissioner Mike Bush said arming the police would change the police's relationship with the public beyond repair.

He said it was incorrect to say that the Police Association was talking on behalf of all police staff.

Photo: RNZ / Diego Opatowski

Mr Bush said it was on police staff's own authority as to how they accessed firearms that were available to them.

"I'm quite sure that the majority of New Zealanders don't want to change their relationship with the New Zealand police."

He said assaults on police staff actually fell 30 percent between 2008 and 2012.

Delegates at the association's conference approved the motion on Thursday, calling on the Commissioner to start the process of arming officers immediately.

A similar call from the association in 2010 prompted the New Zealand police to place guns in lock-boxes inside front-line patrol cars.

Association president Greg O'Connor said guns in patrol cars were still too far away to provide protection for police officers and the public.

"I'm referring to the fact that a police officer was shot just last month.

"I'm referring to the fact that police officers on the street are increasingly stumbling across firearms, just last week two officers visiting an address on a bail check happened across armed offenders."

Mr O'Connor said having firearms locked up was not helpful in an unpredictable situation like the shootings in Canada yesterday.

He said nine police officers had been shot in 18 months.

But Police Minister Michael Woodhouse said he backed the Commissioner's view that police did not need to be armed generally.