The hunt for a missing tramper in Kahurangi National Park will resume with air and ground searches on Friday after rescuers failed to find any sign of him on Thursday.
Four teams searched through Boxing Day night for Palmerston North man Alistair Levy, who has been missing since Monday.
Three more teams joined the hunt on Thursday morning, including a second search and rescue dog.
Sergeant Mike Fitzsimons says police hold grave concerns for Mr Levy.
The police say search teams are focusing their efforts in the very rugged Mount Owen area.
Mr Levy, 54, was last heard from on Sunday when he sent a text message saying he had reached the summit of Mt Owen, west of Nelson.