Tararua and Manawatu-based LandSAR volunteers have assisted emergency services in the search on land and sea for over two weeks, using kayaks and a drone.
Udy, 45, was described as Caucasian, of slim build, and about 155cm tall. She was wearing a nightgown when last seen.
She was not believed to have had access to a vehicle.
Police urged people in the Pahiatua area to remain vigilant and report any further information about Udy to police.