A North Shore police officer leaked secret information from the police computer network to his wife in a bid to win a custody battle with her ex-husband.
An internal investigation found Senior Constable Terry Beatson used the police national intelligence application to open the man's file 17 times over four years.
Unauthorised checking of the network is considered serious misconduct under the police code of conduct and can be grounds for dismissal.
Snr Const Beatson has kept his job despite giving confidential information to his wife, who was in a custody battle with her ex-partner over their young son.
The former husband discovered the leak when he found private details were contained in an affidavit to the Family Court filed by his ex-wife.
The man, who asked not to be named, to protect his son, laid a complaint with Waitemata police in August 2007. However, the matter was not investigated until January 2010, after he made further complaints with the Privacy Commissioner and the Independent Police Conduct Authority.
Police have now confirmed the unauthorised checks by Snr Const Beatson, but would not reveal what disciplinary action had been taken.
Waitemata district commander Superintendent Bill Searle confirmed police had conducted an investigation into inappropriate access of the national intelligence application by a staff member and "strong disciplinary action has been taken, short of dismissal".
Details of the outcome remained confidential between police and the individual, in accordance with employment law.
However, the security of personal information held by police was "paramount", Insp Searle said.
The ex-husband of the woman said he was "totally disgusted" with how long it took for police to investigate his complaint.
While he was pleased the internal inquiry found Snr Const Beatson had breached the code of conduct, he was still disappointed police were keeping some details secret.
"The police have made things really difficult for me over this," he said.
In August 2009, Police National Headquarters figures showed 33 police staff were caught making unauthorised checks of the national intelligence application since August 2007. Nine of those later resigned.
