Police say a house in Linton, near Palmerston North, will remain cordoned off until the middle of the week, while they examine it for evidence over the disappearance of a local man.
Whetu Taeola Hansen, 48, has been missing since 24 November and police have serious concerns for his safety.
A search warrant was executed on 5 December at a property in Akers Road, Linton, which Mr Hansen is known to visit.
Police have been searching the property since Thursday with the assistance of the Defence Force, and have an armed officer guarding the scene.
Detective Senior Sergeant Simon Harrison said the investigation team is tracing his movements and officers are searching the property for any evidence that would indicate Mr Hansen has been there.
He said there are unexplained reasons behind Mr Hansen's disappearance, which he cannot comment on except to say they are a cause for concern.
Mr Harrison said it was not like Mr Hansen to go missing and there was no evidence that his disappearance was drug or gang related.
Local resident Robyn Bland said at least one armed officer has been guarding the property since Wednesday. She said police have put up tents and one of them has stood outside the property with a gun.
Mr Harrison said the deployment of armed officers was for staff security and to protect the integrity of the scene while the thorough examination is being carried out.
He said he wanted to reassure residents that they need not fear for their safety as a result of the police presence.
Some 25 staff are working on the investigation. A team of 15 officers was at the property on Sunday, searching the main house, a self-contained flat on the property, utility sheds and surrounding farmland.