Dale Watene
Detective Sergeant Chris Lucy said 30 LandSar volunteers from Southland and Otago took part in an extensive search at the Longwood forestry block area on Saturday.
"Some areas of interest were identified and further searches are planned."
He said as the weeks passed, "grave concerns" for Mr Watene's well-being continued to grow for both his family and police.
Mr Watene, 40, was last seen on the evening of Thursday, April 16.
He is described as being of thin build and 183cm tall.
He had been using a blue 1995 Isuzu SUV vehicle at the time, which police found on April 18 at Holt Park in Otautau.
Anyone with information was asked to contact Det Lucy on (03) 211 0400, or Crimestoppers 0800 555 111.
