Police charging fewer criminals to meet the Government's crime reduction targets are to blame for the sharp drop in police prosecutions for family violence offences, the Labour Party says.
But the Government and police have strongly rejected this, with Police Minister Anne Tolley calling the claim "unfounded" and a desperate attempt to get a headline in an election year.
New figures issued by the Family Violence Clearinghouse at Auckland University show that charges for male assaults against female, applications for protection orders and prosecutions for breaches of protection orders fell since 2009/10 by between 14 per cent and 29 per cent.
The number of investigations into family violence grew from 86,800 in 2010 to 95,100 incidents last year, but the number of recorded offences fell from 45,000 to 37,900.
Women's Refuge policy and research officer Kiri Hannifin said the sharp decline was "extraordinary", and questioned whether police safety orders, introduced in July 2010, were being used inappropriately and had led to fewer offences being recorded.
Labour's justice spokesman Andrew Little said the numbers were dropping because of pressure to meet Government targets and paint a picture of less crime.
"Front line police and others in the criminal justice system are telling us police have had pressure put on by senior officers to reduce the number of charges they lay to meet the Government's targets," Justice spokesperson Andrew Little says.
"Police are increasingly using pre-charge warnings as a device to not proceed with charges. At the same time I have heard of people being told to gather evidence themselves before police will consider bringing charges."
But Mrs Tolley said the comments were "unfounded and outrageous".
"Police are operationally independent, and politicians cannot and should not interfere in this process. I'm assured that police prosecute where appropriate. Hardworking frontline police staff deserve credit, rather than uninformed criticism from Labour."
Jane Drumm of the Auckland agency Shine said prosecutions had also dropped because of new prosecution guidelines issued by the Crown Law Office in 2010, and updated in 2013, which "raised the bar" of evidence required for prosecutions.
The new guidelines encouraged prosecutors to make "plea arrangements" with defence lawyers where "releasing the saved costs in court and judicial time, prosecution costs and legal aid resources [could] be better deployed in other areas".
However, Police Acting Assistant Commissioner Dave Trappitt said police had always followed Crown Law's prosecution guidelines so the recent changes "did not impact on the decision-making within the police prosecution service".
"Each charge requires the test for evidential sufficiency to be passed before then applying the public interest test," he said.
"This has not changed."