Police firearms have accidentally gone off at least 12 times since 2010, and police have had at least 504 unplanned Taser discharges.

The accidental discharges include the shooting of a man who police were in the process of arresting in the Hawkes Bay.

The numbers of unintentional weapon discharges, which excludes incidents during training, were released by police in response to an Official Information Act request.

They show between 1 July 2010 and 31 October 2016 there were five accidental firearm discharges in operational settings, and seven in non-operational settings.

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Operational is when staff are deploying or responding to an incident, while non operational would be during an administration function - checking or moving a weapon, a New Zealand Police spokeswoman said.

Of the 504 taser discharges in that time, 122 occurred in operational settings and the other 382 happened in non-operational settings, mostly during pre-operational checks or during maintenance.

The police spokeswoman said police were unable to speculate on if the numbers are high or low "as there is no comparable law enforcement agency to compare the numbers with".

"While all steps are taken to avoid the accidental discharge of a police issue firearm or taser it does happen and this is generally due to user or mechanical error."

One shooting happened in 2013 when a member of the AOS accidentally shot a man they were arresting.

Police were called to a Hastings house to deal with a man who had previously pointed a gun at family members.

The man came out and complied with arresting officers, lying face down on the front lawn while police attached plastic hand restraints.

The police officer whose gun discharged had been moving to lift the man from the ground when the shot went off, hitting the man in the shoulder.

The police officer was charged with careless use of a firearm and acquitted after a four day jury trial.

The shooting victim was initially critically injured, but later recovered.

Police Association president Chris Cahill said the numbers were concerning, though the 12 firearm discharges did not seem so high.

"Two a year, it's not a massive number, but it's concerning because they can obviously have pretty dire consequences," he said.

The key to reducing the number of discharges was more training, he said.

Officers needed to become more familiar with the weapons they were using.

The higher number of taser discharges would be partly due to the fact tasers are deployed "a lot more often" than firearms.

Tasers were also being brought into wider use over the period the figures were given for, and would take "a little bit of getting used to.

"You'd think that number should be decreasing over time."

Cahill said accidental firearm discharges would normally happen during loading and unloading.

Both of the figures "probably come down to a training and familiarity thing", he said.