A 12-year-old girl hiding in a kindergarten after midnight was bitten by a police dog when she refused to respond to an officer's calls.

The child was one of 29 youths to have police dogs used against them in just six months, a statistic the Children's Commissioner says is "surprising" and the Maori Party says is "completely unacceptable".

Tactical Operations data obtained by the Weekend Herald shows youths made up 20 percent of incidents where dogs were used. Of those youths, more than 60 percent stated their ethnicity as Maori.

In general, Maori were 12 times as likely to face a dog than Pakeha.

Interactive visualisation and data analysis by Mark Hanna based on the data released under OIA.

Maori were also more likely to be hit by a baton, shot with a taser or blasted with pepper spray, the statistics showed. Overall, a person who was Maori was seven times more likely to incur the use of force by police than Pakeha. Pacific Islanders were also more likely to encounter force, at a rate of 3-1.

Maori Party co-leader Marama Fox said the statistics were in line with what was well-known about Maori over representation in the justice system, but it was troubling to hear the disparity extended to children - including Pasifika children.

"It surprises me we would have to used a dog to subdue a child," she said.

"There may be circumstances as to why. But on the face of it that seems completely unacceptable to me."

Children's Commissioner Andrew Becroft said he was particularly surprised at how many times dogs had been used against 12 and 13-year-olds, but again, it was difficult without more details.

"That said I would expect there would be a clear policy for the police as to how police dogs - and for that matter tasers and pepper spray - are deployed when it is known to the police officer the person is a child."

Police said use of force was only a last resort; that police were to use the least amount of force possible; and any use was based purely in response to the person's behaviour and actions at the time - no their age,  gender or ethnicity.

"Using force against someone under the age of 16 is something we approach extremely carefully," Superintendent Chris Scahill said. "It is always extremely sad and difficult for our staff when having to attend incidents involving very young people."

In the case of the 12-year-old girl, a Pacific Islander, Counties Manukau police were alerted to reports of three offenders, ages unknown, breaking into vehicles and attempting to steal a car in the early hours of the morning in July last year.

A police dog was used to track the offenders, who were repeatedly warned to surrender, to a childcare centre, where the dog was released.

"At the time, the officer assessed that he was dealing with multiple offenders, of unknown ages, who it was believed could have had weapons, who also were in darkness and outnumbered him," police said.

"There were also multiple hazards in the area, including playground equipment and other objects that could have been used as weapons against the officer."

It was only when the dog had apprehended one of the offenders that the officer realised it was a young girl. The dog was immediately recalled and the girl's bite wounds were treated at the scene.

The tactical options data covered more than 2500 events between July and December last year.

Of responses that required force, the data shows "empty hand" was the most common option used, with batons the least common.

The information was provided by police with the caveat it was raw data, and therefore may be "incomplete and unreliable". However analysis showed it aligned with previous data from 2014, where Maori were also heavily over represented in the statistics.

Fox said the data showed that even though the Police Commissioner has acknowledged unconscious bias as an issue,  there was more work to be done and called on the police minister to address it.

"It is appalling to think that Maori are seven times more likely to have force used against them than Pakeha, and for the same types of crimes," she said.

"We need to get rid of unconscious bias, or in other words institutional racism."

Police Minister Paula Bennett said it was an "unfortunate reality" that Maori were over-represented both as victims and offenders throughout the justice and social sectors.

"This is something that we acknowledge and we continue to progress a number of initiatives in this area."

Tasers continue to be used against mentally ill

Police used Tasers against people threatening suicide nine times in six months, latest data shows.

Four of those were taken to hospital with  injuries to the neck, face or stomach caused by the Taser's probes, according to "tactical options" information released to the Weekend Herald.

It comes just after a ruling by the Independent Police Complaints Authority earlier this month, where a sergeant's use of a Taser on a mentally ill man in South Auckland was deemed "excessive and unjustified", and has brought a renewed plea from mental health experts for better resources.

Chief executive of the Mental Health Foundation Shaun Robinson said it had been concerned about the use of tasers on the mentally ill since the weapons were first trialled in New Zealand in 2008.

"The data is really clear that tasers are used more on people with mental illness or those in crisis than others. It's a long term issue," he said.

"We appreciate police are aware of the issue but it's been going on for nearly a decade, and these figures and the recent inquiry show the problem is still extremely real."

Robinson said part of the issue was that police were attending more mental health crisis call-outs, as the health system's resources were stretched.

"Police are filling the gap and that in itself is not ok as it's not their primary role," he said.

"But Tasers are not a good start in caring for people who are unwell and we would be calling on police to do more to equip officers to do better."

Police superintendent Chris Scahill said while police received training in assisting to deal with people suffering mental distress, they were not health professionals, and instead focused on de-escalating a situation.

"Their priority in any situation is to respond to the behaviour they are confronted with at the time, which may be violent, threatening, or be putting the subject themselves, our staff or the public at risk," he said.

That was done using the least amount of force possible, with officers largely resolving incidents peacefully through communication.

" Police experience and evidence collected over the past six years continues to show that where a person is being violent or threatening, the Taser is one of our safest and most effective options for the de-escalation of these incidents," he said.

Of the approximately 2500 events where force was used in the six months to December 2016, 25 percent of those included either the presentation or discharge of a Taser. Maori were eight times more likely to have a Taser presented or discharged against them than Pakeha.