"Dehydrated and a disorientated", missing German hiker Monika Billen was given a lift by an Alice Springs motorist, according to NT Police.

Key points: A motorist says Monika Billen, 62, accepted a lift and was dropped off at the Olive Pink Botanic Gardens without water on January 2

A motorist says Monika Billen, 62, accepted a lift and was dropped off at the Olive Pink Botanic Gardens without water on January 2 Police will resume searching for the missing German in various locations across the Red Centre Friday tomorrow if Thursday evening yields no results

Police will resume searching for the missing German in various locations across the Red Centre Friday tomorrow if Thursday evening yields no results Witnesses have also said the tourist may have visited the East MacDonnell Ranges spot of Emily Gap

A search for the tourist who has been missing in Central Australia for more than a week has yielded a number of witness sightings.

Ms Billen, 62, reportedly accepted a lift from a driver on January 2 at the intersection of Undoolya Rd and Stuart Tce, next to the Todd River in Old Eastside.

The motorist said they also offered her a drink of water, which she declined.

They then dropped her off at the Olive Pink Botanic Garden.

"She requested to be dropped off at Olive Pink on Barrett Drive and that was where she was last seen," NT Police said in a statement.

"Police are calling for anyone who was in these areas or may have dashcam footage that could assist with investigations to contact them."

Tourist spotted on remote walk

Missing woman Monika Billen was spotted at Emily Gap near Alice Springs on January 2. ( island home: Flickr )

Another witness account has placed Ms Billen at the tourist site of Emily Gap, in the East MacDonnell Ranges, on New Year's Day.

NT Police Acting Superintendent Pauline Vicary said police were trying to ascertain how she travelled to the site, 15 kilometres from Alice Springs.

"What we are trying to clarify is if she walked or if she used transport to get to Emily Gap," Acting Superintendent Vicary said.

"We have a witness who say they saw her at Emily Gap that afternoon, but I cannot confirm if she stayed there the night."

Police have been using drones to scour the vast land mass over the Ross Highway, Emily Gap, Tunks Road, Barrett Drive and surrounding areas.

New information has indicated Ms Billen was wearing a yellow cashmere scarf over her head and shoulders to protect her from the sun and heat.

Police to continue search tomorrow

Police distributed this dated photograph of missing woman Monika Billen. ( Supplied: NT Police / Facebook )

Ms Billen was last seen by staff at the Desert Palms Resort, where she had been staying, on January 1.

Staff did not alert police of her disappearance until January 8, despite the fact she was meant to have checked out of her room by January 5.

She also missed a flight booked to Darwin on January 5.

The Desert Palms Resort was contacted for comment but declined as it is still assisting police with enquiries.

During a search of her room, police found brochures for walking trails, including the Larapinta Trail, leading them to believe she may have gone hiking.

Police said if Ms Billen was not found Thursday night they would continue searching Friday.