Specialist cavers and a rescue helicopter will today resume their search for a tramper missing in Kahurangi National Park near Nelson.
Search coordinator Sergeant Mike Fitzsimons said police held grave concerns for the welfare of Alistair Levy, 54.
Seven search teams spent yesterday searching for him but found no trace.
Police said Mr Levy left Nelson on Saturday morning. He sent a text message on Sunday to say he had reached the summit of the 1875m Mt Owen and has not been heard from since.
The Palmerston North man was due to pick up his bike from a cafe in Kohatu and cycle back to his car at the start of the track at Courthouse Flat, but never made it.