Clements was dropped off at the start of the Te Aroha Track on Double Hill Run Rd on May 18.
He was due to get picked up at Lake Emily, south of Mt Hutt, on Monday morning, May 20, but did not arrive.
Police were notified that he was missing around 4.45pm on Monday.
Yesterday, 25 LandSAR volunteers were searching in the area, including two LandSAR dog handlers and a helicopter.
A police spokesperson said this morning that search efforts continued overnight, with six LandSAR volunteers staying the night in the bush, along with a LandSAR dog.
Police Search and Rescue staff were also searching along the Te Araroa Track near Lake Emily.