Police will have 24-hour access to double-shot Taser stun guns during an operational trial of the new technology.
Twenty officers in the Wellington district are being trained to use the new X2 stun guns, which police are evaluating as a replacement for the current X26 model.
The double-shot stun guns can fire a second charge without having to reload, unlike the older model, which need to be manually reloaded after each charge is fired.
They deliver a charge in exactly the same way, through two small prongs which attach to a suspect's body or clothing.
Police demonstrated how the new stun guns will work by firing two charges at a mannequin, dressed in full police uniform, at police national headquarters in Wellington today.
National operations manager Superintendent Barry Taylor said two of the new stun guns would be available to 20 trained officers at all times throughout the six-month trial.
He said the X2 had some important benefits which police wanted to evaluate - including an improved high-definition colour camera and a more advanced built-in computer.
"Assuming the evaluation is successful, the advantage of the X2 is that it would not only provide greater certainty and security for police staff when they confront violent and dangerous offenders, but would also help improve public safety by giving police added capacity to de-escalate high risk situations, including those involving more than one offender."
Mr Taylor said the ability to fire two cartridges was "a clear benefit" which enabled up to four probes to be connected to a suspect at a time - with only two of those probes needed to complete a circuit and deliver a charge.
He said the older model had taken only seconds to reload.
"But you can imagine, in the heat of the moment when an officer is confronting a violent offender, that is just something that we want to take out of the loop. The officer is not placed under that extra pressure of having to reload manually."
There was no risk an offender would get twice the shock because the 50,000 volt charge - the same as the older model - was regulated by the stun gun.
The X2 would only deliver a charge for up to five seconds, unlike the older model, although multiple charges could be given.
Mr Taylor said there had been no technological failures with the older model, although operational errors and environmental factors such as wind could affect connectivity.
Officers involved in the trial would also be issued with body cameras, to be worn on their clothing or glasses.
Mr Taylor said the officer-operated cameras would give an additional perspective to the built-in cameras on the stun guns, which operated automatically for 10 seconds when a cartridge was fired.
"It is significant for the police and the public at large because it gives us a wider spectrum and a wider time-frame than just that 10 second snapshot that is available."
He said there was no move for officers to carry Tasers on them at all times, and officers would still need to do a risk assessment before deploying them.
Police have used Taser stun guns more than 1500 times since they were rolled out nationally in March 2010.
"There's no question that the introduction of the Taser has been a highly successful tool in minimising risk and maximising officer safety and safety to the community for all those involved," Mr Taylor said.