The Ombudsman has begun an investigation into whether Auckland Council improperly delayed the release of a major report to RNZ.
Emails released to RNZ included an executive outlining how refusing to release the report would allow more time to better manage how it went public.
It took RNZ five months to get the report on the economic impact of shifting the imported vehicle trade away from the city, and then only after the Ombudsman intervened.
Chief Ombudsman Peter Boshier said an email exchange about the timing of the release will be an aspect of the investigation.
"We plan to complete the investigation as soon as possible given the significant issues that have been raised," he said in a statement to RNZ.
He said he had already signalled to councils around the country to pay close attention to their management of official information requests.
"This month marks thirty years since the Local Government Official Information and Meetings Act came into force. I have been delivering a strong message to local authorities about the need to lift their game."
RNZ has also raised with the Ombudsman's Office the 15 months it took to obtain paragraphs withheld from a letter written to the mayor Phil Goff by David McConnell - the chair of the council's economic development agency.
The letter, written weeks after Mr Goff's November 2016 swearing-in, expresses displeasure at the mayors public criticism of a global marketing campaign ATEED had developed with the blessing of the previous council.