Police hold grave concerns for the wellbeing of a German tourist not seen since leaving a resort in Alice Springs more than a week ago.
Monika Billen, 62, failed to check out of the Desert Palms Resort on Saturday, January 5 and board a plane to Darwin. The hotel contacted police on Tuesday.
She was travelling alone and was last seen by hotel staff on New Year's Day.
CCTV footage from 10.30am shows her out front of the hotel heading south, wearing a red chequered long-sleeve top with denim knee-length shorts and carrying a red backpack, with five cars including two taxis in proximity.
Police are keen to speak with the drivers.
Ms Billen is described as having a slim build and short grey hair.
Police have been using drones to help search bushwalks around the town, including the Larapinta Trail, as she had walking brochures in her hotel room.
Superintendent Pauline Vicary said there was no evidence to suggest anything suspicious had occurred but police were concerned.
"We continue to hope we will find her alive but we are gravely concerned about the recently hot conditions," she told reporters.
"We understand Ms Billen may have had some interest in walking the Larapinta Trail or local bush trails."
Temperatures have been consistently above 40C in central Australia over the last week.
Police have contacted the Germany Embassy and asked them to contact Ms Billen's family.