In his complaint to the Ombudsman, Reti said WDC did not provide emails from 2014 and 2015 that showed it was actively interested in acquiring the piece of land on which the state houses would be built.
The Whangārei MP said that bit of information was contained in a separate Official Information Act (OIA) request on a similar issue he forwarded to Housing NZ.
Reti said the other information WDC 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.
In a letter to Reti, the Ombudsman's office confirmed it was investigating his complaint.
"I have written to the chief executive of the council to commence the investigation. I have asked for the relevant information and the reasons for the decision," senior investigator Victor Lee said.
Housing NZ expects to lodge a resource consent application with the Whangārei District Council in April, and start earthworks in spring, with construction early next year and the new homes ready in early to mid-2021.