People will be able to go to police and ask if their partner has a history of abuse under a new disclosure scheme - receiving a response within 24 hours in the most serious cases.
If people are concerned about their safety they can now approach police either in person or by phone and ask about their partner's history.
Police will consider disclosing information on a case-by-case basis if it is legal and will protect the potential victim.
If there is a serious threat to the safety of a person or their children then a decision will be made within 24 hours, with other decisions coming within 20 working days.
A third party, such as a parent or friend, can make an application but they would not necessarily receive the information about the individual concerned.
According to the police website, it may be considered more appropriate for the information to be provided to the partner or "another person who is best placed to protect the potential victim".
The new disclosure scheme was announced by Justice Minister Amy Adams and Police Minister Judith Collins, and is part of a range of measures designed to reduce domestic violence.
"There have been too many cases where concerned family and friends haven't been able to find out whether someone they know or live with has a history of family violence," Ms Adams said.
"This is a practical, potentially life-saving initiative that aims to increase the safety of people in a relationship with potentially violent partners. It will help people make informed choices about whether, or how, they continue the relationship."
Ms Collins said the Official Information and Privacy Acts already enable police to disclose such information.
"This scheme is about improving the quality of service that police provide to potential victims."
In August, Ms Adams told the Herald that government officials and those working with children and families are often over-cautious when it comes to sharing information.
She pointed to the coroner's rulings on Edward Livingstone's murder of his two children before killing himself last year.
"Coroner [Deborah] Marshall made the point quite strongly that one of the significant failings in hindsight was the lack of information-sharing between people who had interacted with the family. Now I think the need to do that has been raised loudly and clearly."