The 50,000-volt stun-gun to be tested by police next year has several weaknesses.
The Taser gun has a limited range and is not effective through heavy or non-conductive clothing.
It is also unsuitable for use near water, in large crowds or in certain weather conditions, such as heavy wind or
rain. But despite those weaknesses, a visiting British police officer said the Taser gun - which was used to subdue a suspected terrorist in London last month - was a useful tool that could help officers do their job more safely.
Police Federation of England and Wales chairwoman Jan Berry, who is visiting the Police Association, said England tested the Taser about 18 months ago and now used it with great success. A stun-gun was not always called for, Ms Berry said, but the mere sight of the Taser's red laser was often enough to make offenders surrender.
New Zealand police will test the guns next year to see if they can help to deal with the increasing number of violent offenders.
The trial is supported by the Police Association, which says officers have found weapons such as pepper spray often do not work on violent or aggressive people.
Association president Greg O'Connor said officers had few other tools available besides firearms, which were usually deadly.
"Police are feeling vulnerable, not just because of the physical confrontation but because of the consequences of it - the complaints that emanate from it," he said. "Anything which gives us another option to avoid physical confrontation is good."
Stun-guns have been considered for several years and the device was one of several tactical options mentioned after the fatal shooting of Waitara man Stephen Wallace.
The Taser is designed to subdue people by hitting them with a charge that makes the muscles contract uncontrollably.
Police plan to introduce stab-proof vests next year. Officers have been calling for such vests for several years, saying they are facing increasingly violent people, especially since P (pure methamphetamine) has become popular.
Some police are so concerned about their safety they have bought their own vests over the internet for several thousand dollars.
Money for the vests was allocated in the Budget.
