Five teams of volunteers were deployed overnight in an area of the Tararua Forest Park where a Chilean tourist is missing.
Police say the man became disoriented in the vicinity of Mount Holdsworth, west of Masterton.
He lost the track returning from a day hike and used his cellphone to call for help, but low cloud prevented a helicopter search.
Police say he was not equipped for an overnight stay in the park, but the weather is mild.