The Chief Ombudsman is siding with the Government when it comes to disclosure of information around former Northland MP Mike Sabin.

The issue caused a political firestorm last year after then Police Minister Michael Woodhouse refused to give any specifics about what he was told, and when, by police about an investigation into Mr Sabin.

Opposition parties have alleged the Government may have known about the matter before the 2014 election, and before Mr Sabin was appointed chair of Parliament's Law and Order Select Committee

Newstalk ZB has taken the issue to the Ombudsmen, but Chief Ombudsman Peter Boshier has ruled disclosure of details would prejudice maintenance of the law.

He's declined to give full reasons for his ruling, saying they would likely prejudice those interests as well.