Waikato police say they do not have a clear area to search for a Te Kuiti man missing for near six-months.
Colin Heath, 46, was first reported missing on 19 March and was last seen in his King Country home town.
Police said his bank accounts had not been touched and inquiries into his whereabouts had been unsuccessful.
They said other efforts to find Heath, including reviewing telecommunications, had also failed.
Police, and Heath's family were extremely concerned for his well-being given the length of time time he had been missing.
They said they were keen for any information from the public, regardless of how small people thought it was, as it could be relevant to the investigation.