Maurice Williamson and Police Minister Anne Tolley received early warning from police of potential issues around Donghua Liu under their "no surprises" policy.
Ms Tolley was told of the Herald's Official Information Act request, which prompted police acknowledgment of Mr Williamson's intervention more than two weeks ago, police confirmed yesterday.
Mr Williamson and Ms Tolley received more detailed information from police on Monday.
Police said they made a "brief mention" of Herald reporter Jared Savage's request seeking information about Donghua Liu in their weekly report to Ms Tolley on April 14 under the "no surprises" policy. No further details were given of the nature or scope of the request, police said.
On Monday this week - four days after police had declined Savage's request and he made an urgent appeal to the Ombudsman - they provided Mr Williamson with a copy of his request. They also told him they intended "to release relevant information with appropriate redactions to the NZ Herald and that a copy of the information to be disclosed will be provided prior to public release".
The same day, Police Commissioner Mike Bush told Ms Tolley - again under the no surprises policy - of the details of the OIA request. Mr Bush also briefed the chief executive of the politically neutral Department of the Prime Minister and Cabinet, Andrew Kibblewhite, on the OIA request.
On Tuesday, Mr Williamson's office was provided with a copy of redacted emails between three senior officers that police proposed releasing to the Herald. Police also provided Prime Minister John Key's office with copies of the email exchange that began with a message from the top policeman for Mr Williamson's electorate, Counties Manukau district commander Superintendent John Tims, despite Auckland Central being the investigating station.
Ms Tolley received a copy of the emails and Savage's original request on Wednesday.
Early yesterday, police reassessed the OIA request and considered the public interest to make the information available outweighed other considerations.
A Labour spokesman said: "From our experience in government it was police practice to give the Minister of Police a 'no surprises' briefing on events that could involve high-profile matters. These occurred around the time of the particular incident."