They would not say what they believed had happened to Mr Hansen but were concerned for his safety, for "unexplained reasons".
Detective Senior Sergeant Simon Harrison, in charge of the investigation, said Mr Hansen was last seen driving the ute in the direction of Palmerston North on November 24.
"Sightings of this vehicle form an important part of our inquiries in terms of piecing together Mr Hansen's movements and we want to hear from anyone that saw the vehicle between the Sunday and Thursday, December 5."
The examination at the Akers Rd property continued yesterday and police were making good progress given the significant size of it, Mr Harrison said. A team of 15 officers supported by ESR staff were involved in the examination.
Mr Harrison said police were continuing to speak to Mr Hansen's family and his associates but had not yet found him.
"At this stage we have not been able to locate Mr Hansen but we have had some calls from the public regarding our investigation and we are grateful for these, as well as the support of media in our appeal.
"We are still keen to hear from anyone that may have any information about his disappearance or sightings of the vehicle and I encourage them to contact police," Mr Harrison said.
Mr Hansen is described as being of Maori descent, medium build, approximately 1.72m tall, with brown eyes and dark greying hair.
It is not known what clothing he was wearing when he was last seen.
Anyone with information about Mr Hansen's whereabouts, or sightings of his ute, should contact Detective Dave Wilson 06 213 9595. Information can also be provided anonymously through the Crimestoppers hotline on 0800 555 111.
