Reti said that bit of information was contained in a separate OIA request on a similar issue he forwarded to Housing New Zealand.
Reti said the other information the council did not supply him concerned a telephone voice mail from a council employee to Land Information New Zealand.
He said that information came to his attention through a Housing NZ email.
The Ombudsman's office this week confirmed Dr Reti's complaint was resolved after the council provided the information he asked for.
"This meant the Chief Ombudsman was able to discontinue the investigation and close the file without making a formal finding on the complaint."
In a letter to Dr Reti, council chief executive Rob Forlong apologised for the non-disclosure of material but said that was entirely unintentional.
He said the council was committed to meeting its regulatory obligations under the Official Information legislation and he had recently reminded staff of the importance of conducting thorough searches in response to requests.
Forlong said because of Reti's previous concerns about missing documentation, in addition to seeking material from key departments, council staff also undertook a forensic search of its archival email system.
That search involved a time-consuming and resource-intensive process of bulk extraction of potentially relevant emails, manual review of an excel spreadsheet, and a further process of extracting individual emails.
Housing NZ plans to build 37 mostly double-storey houses on 32,730sq m of land adjacent to public park - a move that has angered residents living on Puriri Park Rd who say it will lead to a loss of a green space.
A resource consent application lodged with the council has been publicly notified.