Searchers in Hong Kong will keep looking for a missing Air New Zealand pilot until at least the middle of this week.
Steve Morrissey has not been seen since Wednesday. The 51-year-old was tramping with another New Zealander on the Wilson Trail in the hills of the New Territories region.
The track is considered to be easy but temperatures in Hong Kong have been above 30 degrees Celsius.
Abseiling specialists and boats were again used in the search on Monday.
The divisional commander for the Tai Po police station, Ricky Ho, says the search has involved more than 100 people.
Mr Ho says it has been decided to continue looking for Mr Morrissey until at least Wednesday when the situation will be reassessed.
Mr Morrissey has a cell phone with him and Air New Zealand says police have worked through all options in trying to track it, though the battery is now likely to be flat.
Air New Zealand staff and Mr Morrissey's family have been helping in the search.
Air New Zealand's chief pilot, David Morgan, says Mr Morrissey is fit and well versed in survival techniques.
He is a former member of an Air Force helicopter squadron and was deployed in Singapore.