The rest were either dealt with via non court action, formal warnings or informal warnings.
The figures for May and June were not available.
New Zealand has the worst rate of family and intimate-partner violence in the developed - and sadly more than 80 per cent of incidents go unreported.
In a bid to curb family violence the new offences were introduced to make specific acts a criminal offence.
Previously there was no separate offence for strangulation or assaulting a family member.
Instead, those offence were treated as standard assaults.
The change was part of the Family Violence Amendment Act, replacing the Domestic Violence Act.
Other police statistics related earlier this month show that in 2018 police conducted 133,022 investigation's into family harm.
Of those, 37,599 offences were established, 19,801 people arrests and 16,254 prosecuted.
In 2017 121,762 investigations led to 39,690 offences being identified, 21,606 arrests and 16,863 prosecutions.
Police also revealed that one third of all those investigations occurred in the Auckland region.
"Family harm, of which family violence is a subset, is a far-reaching social issue in New Zealand," a police spokesperson said, adding police are committed to reducing the prevalence and impact on families, including but not limited to domestic violence.
"We have dedicated staff who, in partnership, provide specialist services to support victims and offenders alike with the goal to break the cycle of harm in our highest risk communities."
Police harm reduction manager Inspector Fleur de Bes earlier told the Herald that family violence was a "significant" issue for all New Zealanders.
"With police attending one family violence episode every four minutes - based on 2018 figures, this means that it is likely that someone you know will be affected," she said.
"The seriousness of this crime has most recently been highlighted by the significant volume of strangulation offences that have been identified by police since the new strangulation offence was introduced on December 3.
"Police have filed an average of 33 strangulation charges before the Court each week.
"This is a shocking statistic."