Christchurch police say they are concerned for the well-being of a British tourist who is overdue while walking the Te Araroa Trail between Nelson Lakes and Boyle River.
Andy Wyatt, believed to be about 24, was last seen at Blue Lake in Nelson Lakes National Park about 13 December.
Senior Constable Phil Simmonds said on Thursday Mr Wyatt was intending to tramp to Boyle settlement in the Lewis Pass, where he was due to pick up a food package three days later.
Another tramper spoke with him at the Blue Lake hut, but he has not arrived at Boyle settlement.
Police and land search and rescue are checking huts and tracks on the trail on Thursday.