Tamra McBeath-Riley, 52 was found after police located the vehicle the trio were travelling in bogged the bed of the Hugh River.

Police have sent out two helicopters this morning to search for the other two people still missing in outback central Australia.

Ms McBeath-Riley was found after police located the vehicle the trio were travelling in bogged in the river bed.

Her two friends are still missing, after 13 days in the outback, believed to have been walking in a different direction to get help after their car became bogged.

Police today said Claire Hockridge and Phu Tran remain missing and are believed to be severely dehydrated.

Ms McBeath-Riley has been taken to the Alice Springs Hospital where she will receive treatment for dehydration and exposure.

Claire Hockridge and Phu Tran remain missing in the area and police were stepping up their search efforts in hope to finding the pair.

The trio and their dog failed to return from a day trip into the local bush last week.

Anyone with information as to the whereabouts of Claire, Tamra and Phu are urged to contact police immediately on 131 444 or report it anonymously via Crime Stoppers on 1800 333 000 reference PROMIS number 9140905.

The three had told friends and family they were going for a drive south of Alice Springs, but failed to return that night.

The group were travelling in a white Mitsubishi dual cab Triton ute with South Australian registration S483 AAI.

The vehicle has a black soft tonneau cover, a front nudge bar with two round lights, a UHF aerial and a black bonnet strip.

A pet grey/blue coloured Staffordshire bull terrier is with the group, and it is not known what supplies of food or water, if any, they had taken with them.

Locals Claire Hockridge, 46, Tamra McBeath-Riley, 52, and Phu Tran, 40, went missing from Alice Springs on Tuesday, November 19.

NT police have failed to find them even after an exhaustive search by air and land after they were reported missing on Saturday, four days after they were last seen.

Temperatures over the past week have reached extreme levels or more than 40 degrees on some days.

Ms McBeath-Riley was found alive by a search team 1.5km from the bogged car the group had been driving.

ABC is reporting today a note left in the car said the missing pair went in a westward direction, which has allowed police to narrow the search.

Ms McBeath-Riley was found east of the Stuarts Well area, south of Alice Springs, late yesterday near some water.

Superintendent Pauline Vicary said police also found the vehicle the trio were travelling in and understand the car became bogged while the group was out for a drive.

The vehicle was found during an air search after a pastoralist told police they had spotted tyre tracks nearby, ABC says.

Police said it appeared Ms McBeath-Riley had gone north of the vehicle and the others had gone west.

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