Customs developed a special process for releasing public information to the media which included an increase in delays and the freedom for its Cabinet minister to change whatever was released, according to documents provided to the Herald.
The papers (see below) detailing Customs processes for handling Official Information Act requests show it built in a 10-day buffer to give its minister more time to respond.
It signalled there were special steps to be taken for requests for information from politicians, news media or lobby groups.
The OIA is overseen by the Office of the Ombudsman and will soon see Chief Ombudsman Dame Beverley Wakem conduct an inquiry into the way it is handled by ministerial offices and government departments.
The OIA was made law in 1982 to provide a way for the public to have greater involvement in the way government works by accessing information about decisions which are made.
The Herald sought details on Customs' process after the agency's former general counsel Curtis Gregorash came forward in the closing days of the election to say he quit working there because of its handling of OIAs.
Mr Gregorash said he spoke out because of an instruction that he claims he was given to effectively bury bad news which was to be released through the OIA, primarily for political reasons.
Customs OIA processes (App users click here)
He alleges that: "The direction came down (from the minister) through the CEO (Carolyn Tremain) and group manager (of legal services) Peter Taylor to me saying 'you don't release anything - I don't care what the OIA says, I'd rather fight it in the courts'."
The policy stipulates the minister has to be briefed on requests from politicians of any party, research units, lobbyists and media. It stated the minister wanted a copy of the draft response and his staff would provide feedback "for appropriate review and possible revision".
LISTEN TO AUDIO INTERVIEW WITH CURTIS GREGORASH
The papers which described the way Customs handles OIA requests - which can be made by any member of the public - showed a policy change in September 2012.
Under the law, government departments are meant to provide information as soon as possible but no later than 20 working days.
But the Customs policy shows the imperative to respond with speed ran into an new system which gave staff just 10 days to handle requests because the communications staff and minister's office wanted the remaining 10 days.
"Please be aware that this will lead to an increased number of requests for extensions of time (these will need to be explained)."
Prime Minister John Key recently came in for criticism after Radio NZ received papers on child poverty 17 months after they should have been released.
Mr Key said the government would sometimes delay the release of material. "Sometimes we wait the 20 days because, in the end, Government might take the view that's in our best interest to do that."