"That has been the trend over many years. I think everyone would agree," Acting Superintendent Dave Campbell said.
The Government is considering harsher sentences for offenders who attack police officers, with Police Minister Judith Collins yesterday saying she will consider a law change to better protect police officers.
She said she would look at tougher penalties, but rebuilding respect for the law should be the first step.
"What I've asked to find out is whether or not the law is being properly applied. That's one side of it.
"But, actually, we'd rather stop the attacks in the first place, and I think it's extremely important that we start to rebuild the respect and fear for the law that we expect," she told Radio New Zealand.
A police report about increases in acts of violence against its staff is due to be received by Mrs Collins at the end of the week.
The report was called for after Senior Constable Jeremy Snow was shot when checking a suspicious vehicle in South Auckland in December.
Urgency was added to the matter after three police officers were attacked in separate incidents at the weekend.
Three men were charged and released on bail yesterday over an assault on a police officer at an Oamaru drink-driving checkpoint on Sunday night; off-duty officer John Connolly was left seriously injured with broken bones after trying to break up a fight south of Auckland and having bystanders turn on him; and, near Whangarei, a police officer had part of his lip bitten off when he tried to breath-test a suspected drink-driver.
Prime Minister John Key yesterday condemned the attacks and said the country would have been appalled.
"They were barbaric acts and quite frankly they were disgusting, and if anyone thinks the Government is going to sit back while police officers' lips are being bitten off and do nothing about it then they need to think again," Mr Key said.
He said penalties against those who assaulted police would be reassessed, including whether it should be mandatory that such attacks be an aggravating factor in sentencing.
The law gives judges discretion on whether that should be the case.
Acting Supt Campbell would not be drawn on whether he would like to see harsher penalties for people who assault police.
However, he said assaults on the police in the southern district were common, although the number of people charged with assaulting police in the Dunedin-Clutha police area declined last year compared with 2008.
There were 96 assaults on police in the Dunedin-Clutha's district in 2008, with 12 people facing the more serious charge of assault under the Crimes Act and 84 people charged with assault under the Summary Offences Act, a crime with a lesser penalty.
Last year, there were 74 assaults on officers.
Nine people were charged with Crimes Act assault and 65 with Summary Offences Act assault.
Nineteen officers recorded injuries received while on duty, another four while dealing with a prisoner in custody and seven recorded injuries received in other circumstances, mainly while transporting psychiatrically disturbed people.
Most of the injuries were cuts, bruises, sprains and bites.
Mr Key said statistics showed nationwide there were 216 assaults on police in 1999-2000, compared with 412 in 2008-09.
Firearms offences against police had grown from 19 to 41 in that period.
His thoughts on the increase in violence towards police was that it reflected increased drug and alcohol abuse.
An 18-year-old Dunedin man was charged with assault after a police officer was bitten on the leg on Saturday.
The intoxicated youth was spoken to by police after reportedly trying to enter a South Rd dairy about 1.20am.
He was taken to Dunedin Hospital when he passed out, but once there he rallied and bit the officer on the leg, breaking skin.
The officer received medical treatment.
