The chances of a five-year-old girl who was allegedly abducted surviving are getting lower by the day, NT Police warn.

Police believe Sharon Granites was likely kidnapped by 47-year-old Jefferson Lewis, who had been released from prison just six days earlier, from a home in the Aboriginal town camp of Old Timers, on the outskirts of Mparntwe/Alice Springs, on Saturday night.

Her mother is being cared for by mental health professionals, while her father — who is currently incarcerated nearby — has been updated on the search.

Speaking to ABC Radio as the search enters its fifth day, NT Police Commissioner Martin Dole acknowledged that, based on the knowledge of bush experts, Sharon's chances of survival are now "starting to become quite concerning for people".

"We do consult people for survivability, and that's what gauges our search areas," he said.

"So we're getting to the end of that timeframe of survivability unfortunately, but that doesn't mean our search efforts are going to reduce significantly because like I said anything is possible in these scenarios."

Mr Lewis was seen holding Sharon's hand at 11 pm, before she was put to bed. She was reported missing at 1.30 am Sunday morning.

Commissioner Dole said police remained adamant Mr Lewis was still in the Alice Springs area.

"The evidence is the lack of information, it is the absence of any sightings ... that is highly unusual," he said.

Mr Lewis is known to have links to several remote outback communities in the NT and WA. WA Police were deployed to the remote Kimberly community of Balgo, where he is reported to have family, but found no sign of him.

Having been released from prison, Mr Lewis was told to go to Lajamanu, where he has family. It's understood he was not welcome back in the remote community of Yuendumu — two-and-a-half hours north-west of Alice Springs — because of his offending.

Instead, he elected not to travel to Lajamanu, a dry community 560 km south-west of Katherine, instead going to Old Timers to see some extended family.

On Wednesday, the Nine papers reported Sharon's kinship grandfather Robin Japanangka Granites believed the alleged abductor walked through the house and took Sharon through a gap at the rear of the property, which backs onto the Todd River.

He also told the ABC: "A very terrible thing, a horrible thing, and we wanted to try and see if we could get her back, but we can't."

"[We've been] crying, crying, and doing what we meant to be doing, and being out there with our family crying... and that's not what we want, we want to be going out and searching for her. She's only a little baby," he said.

Multiple family members have said Sharon is non-verbal, communicating mostly through hand signals.

Commissioner Dole acknowledged this complicates the search, noting if she is still with Mr Lewis, "she's unable to communicate needs".

He reiterated police are adamant people in the community are helping Mr Lewis — who does not have a bank account, car or mobile phone.

"There's people out there who are assisting, and that do know something, and that aren't feeding that information into the authorities," he said.

A number of items were recovered Wednesday on the banks of the Todd River, including "a doona cover, the shirt that Jefferson Lewis was wearing — it was a distinct yellow one — and we seized a pair of child's underwear from that location," according to Assistant Commissioner Peter Malley.

Commissioner Dole said the forensic evidence results for some of those items should come back today.

"They're being forensically tested for DNA to see if we can confirm or exclude DNA attributed to Sharon and attributed to Jefferson," he said.

Scores of police officers, Aboriginal trackers, defence force members and volunteers are combing tough desert terrain for the young girl. On Wednesday, police said search teams had covered around five square kilometres on foot.

Federal Minister for Indigenous Australians, Malarndirri McCarthy, who has been in Alice Springs helping with the search, told ABC Radio they were "grateful for the coming together of the Alice Springs community in working with Northern Territory police and emergency services and with Tangentyere Council".

In a message to the community who may have information, Commissioner Dole said: "Don't be scared".

"You might be fearful that there's some retribution if you give that information to police," he said. "Please have the confidence that we will treat that sensitively, because our number one priority is finding Sharon."

Anyone who knows the whereabouts of Mr Lewis or Sharon, or who has any information at all, is urged to call police on 000. Please quote reference P26120934.

Anonymous reports can be made through Crime Stoppers on 1800 333 000 or via https://crimestoppersnt.com.au.

1800 RESPECT (1800 737 732)

National Sexual Abuse and Redress Support Service 1800 211 028

Lifeline (24-hour crisis line): 131 114

Full Stop Australia: 1800 385 578

Beyond Blue: 1300 224 636

Ruby Gaea (NT): 08 8945 0155