Police are scaling back the search around Alice Springs for missing German tourist Monika Billen, who they have been unable to find after five days of looking.
The 62-year-old woman has now been missing for 12 days, with witness accounts putting her last sighting around Emily Gap in the East MacDonnell Ranges on the afternoon of New Year's Day.
However a woman told police she gave Ms Billen a lift in a car the previous day and thought she looked dehydrated and disorientated, but she declined the offer of water.
Temperatures have been consistently above 40C in central Australia over the last fortnight.
Superintendent Pauline Vicary said aerial searches will be suspended after police had exhausted all locations of interest but enquiries would continue.
"In the past five days Northern Territory police have covered vast tracks of land via aerial and land searches," said Supt Vicary
"Unfortunately despite our efforts no further evidence has been found to indicate Monika is still out there.
"Neither is there any evidence to indicate foul play.
"We cannot stress enough to motorists, pedestrians, cyclists - anyone who believes they may have information that may assist with our investigations."
Police were contacted on January 8 after she failed to check out of her hotel and board a flight to Darwin.