"This is something I know New Zealand is ashamed of and the Government is taking a major step forward in fixing on the budget."
The $320 million has been allocated over four years.
It includes almost $50 million towards preventing family violence and sexual violence and $85 million towards creating a safe, consistent and effective response to family violence in every community.
More than $130 million has been set aside for expanding essential specialist sexual violence services and to moving towards fully funding services.
Almost $40 million has been earmarked for reforming the criminal justice system to better respond to victims of sexual violence.
The family and sexual violence package, which sits across eight portfolios, is the result of the first ever joint Budget bid from multiple government departments.
Today's announcement comes as part of the Government's Wellbeing Budget, to be unveiled in full on May 30.
"Wellbeing means being safe and free from violence," Ardern said.
"That is why this package is such a significant cornerstone of the Wellbeing budget."
Ardern said her goal has always been for New Zealand to be the best place in the world to be a child – "that means supporting parents and communities to ensure children grow up in secure homes free from violence".
The funding covers one million New Zealanders covered by Integrated Safety Response sites in Christchurch and Waikato.
It also caters for 350,000 people in the Whāngaia Ngā PāHarakeke and Whiria Te Muka sites in Gisborne, Counties Manukau and Kaitaia.
Jan Logie, Under-Secretary to the Minister of Justice (Domestic and Sexual Violence Issues) said the funding aims to give providers funding security, while making available significant extra resource to break the cycle of violence and provide more women, men and children they help they need.
"We know this is a long-term project. The package we're announcing today lays the foundations for a violence-free Aotearoa New Zealand,"
The $320 million across four years will be spent on:
• Expanding essential specialist sexual violence services: moving towards fully funding services – $131.1 million
• Creating a safe, consistent and effective responses to family violence in every community – $84.3 million
• Reforming the criminal justice system to better respond to victims of sexual violence – $37.8 million
• Strengthening system leadership and supporting new ways of working - $20 million