Police Minister Judith Collins says it is sad that Labour leader Phil Goff is trying to take credit for a substantial decrease in recorded crime.
The exchange of verbal blows followed the release yesterday of recorded crime statistics for the year to June which showed a 7 per cent decrease allowing for a rise in population.
Serious assaults, murders, drug offences and family violence offences all dropped, but there was a 12.4 per cent increase in sexual assaults and related offences, and a spike in the number of acts endangering other people.
The number of murders - 34 - was the lowest since records began in 1986, and almost half the previous total of 65 for the year to June 2010.
Mr Goff said the policies of the previous Labour-led Government contributed to the success.
"There's a long time-lag on crime statistics. I think some of those crime statistics will reflect the fact that we have a strengthened corrections system and a strengthened police force, and most of those changes happened under Labour.
"In terms of the murder rate, we had the highest rate on record last year, one of the lowest this year. That's something that Governments don't control."
But Ms Collins said Mr Goff was drawing a "very long bow".
"It's a bit sad that Phil's trying to take credit for something three years after Labour was thrown out of office. The police are the ones taking credit for the majority for this drop in crime statistics."
She said Mr Goff's comments did not square with Labour's condemnation of the Government when violent crime shot up for the 2008/09 year. But she agreed the murder rate was not the best indicator of the level of crime in a community.
"Murder numbers are generally static.
"But one murder is one too many, but 34 in this financial year compared with 65 in the previous is a huge improvement."
The latest figures show that recorded family violence, which had previously been increasing, fell by 3.1 per cent, including a 2.1 per cent drop in family violence assaults.
Ms Collins said the increase in sexual assaults could be a sign that reporting of those crimes was improving, "but there's no evidence either way".
Police say sexual assaults are heavily under-reported.
Recorded crime compared with previous year to June
* Homicide and related offences: Down 23.8 per cent
* Acts intended to cause injury: Down 3.9 per cent
* Sexual assault and related offences: Up 12.4 per cent
* Dangerous acts endangering persons: Up 17.2 per cent
* Illicit drug offences: Down 14.6 per cent
* Total recorded crime: Down 5.8 per cent (7 per cent allowing for population increases)
Total recorded crimes
* Auckland: Down 4 per cent per head
* Counties-Manukau: Down 6.1 per cent
* Canterbury: Down 15.6 per cent