Every year domestic violence spikes at Christmas time and experts predict this year to be no different.
Police and Women's Refuge say factors such as financial stress and alcohol cause some husbands and dads to lash out.
Police figures for the financial year to June 31, 2014 show the number of "assault by male on female" offences in December was 22 per cent higher than the average of other months.
Counties Manukau district family violence manager Senior Sergeant Sharon Price said the annual spike in such offences was expected.
"It's probably an accumulation of things. One thing is the financial stress ... It's putting that food on the table. Alcohol comes into it. The children are off school ... Tensions rise there and that can just explode into family violence.
"We know that it's going to rise in December and January and February. We ... put increased resources into it ... we need to be working."
Police recorded 658 "male assaults female" offences nationally last December. The next highest month in the 12-month July-June period was June this year, with 573.
The police district with the most recorded "male assaults female" offences last December was Counties Manukau, with 90. And the district recorded 94 in January -- the highest monthly number recorded anywhere that year.
"It's okay to be stressed at Christmas, but it's how people deal with that stress," Ms Price said. "Our biggest thing is we want our families to be safe and happy over the Christmas period. But ... for some people the stress just gets too much and escalates into violence."
Kiri Hannifin of Women's Refuge said the refuge would be full this Christmas, as it is every year.
"We're busy all year anyway, we're always full. But Christmas is always quite busy. Financial pressure doesn't cause domestic violence, but it can exacerbate it."
And for the women and children in the refuge at Christmas time, it was never a good time of year, she said.
"I think people's crises are compounded by what is supposed to be the 'Christmas cheer'. There's the extra pressure [for it] to be a happy and joyful time. But ... people are so deeply traumatised, especially the children."
Ms Price said police worked closely with their "partner agencies" to encourage both perpetrators of family violence, and victims, to seek help and report the crimes.
"Families need to know that this support is out there."
Where to get help
Police Emergency: 111
Women's Refuge: 0800 733 843
Victim Support: 0800 842 846
Lifeline: (09) 522 2999
Family Violence Info Line: 0800 456 450