Five-year-old Sharon Granites is believed to have been led away from a town camp in Mparntwe/Alice Springs by 47-year-old Jefferson Lewis after she was allegedly snatched from her home.

Speaking to reporters on Tuesday, NT Police Assistant Commissioner Crime and Intelligence Peter Malley said authorities believe Sharon is still alive. He said Mr Lewis was last seen at 11 pm on Saturday, noting he was "seen with the little girl, holding hands".

"We believe Jefferson Lewis has led the little girl away," Assistant Commissioner Maley said.

The young Aboriginal girl was reported missing about 1.30 am on Sunday after she could not be found at her home in Marshall Court at Old Timers Camp.

Police now believe Mr Lewis abducted her.

Mr Lewis, who was recently released from custody, is known to police for domestic and family violence-related offences. While police say they do not have a motive, they believe he was likely "under the influence of alcohol".

The 47-year-old has only a "loose connection to the family," Assistant Commissioner Maley said, noting they "just happened to be present together at that location on Saturday night".

He said the search is continuing, with the child's wellbeing "remaining the number one priority of the Northern Territory Police".

He described the operation as "one of the biggest investigations we've had going for a while".

"The team has done everything within its power," he said. "It was up and running very, very early. Resources here as part of the search are really significant.

"TRG [the Territory Response Group], motorbikes, horses, helicopters, drones, so it's a significant investigation and search."

Police say Sharon was last seen wearing a dark blue short-sleeve T-shirt with a white ring stripe around the neck and a white ring stripe around the end of the sleeves, along with black boxer-style underwear.

Police believe Sharon is still alive, though Assistant Commissioner Malley acknowledged that "as time goes on, the chances of finding her alive and well, reduce, so hence the amount of resources we have present here in Alice Springs".

NT Police executive director of cultural reform Leanne Liddle confirmed on Tuesday Aboriginal trackers had been called in to assist with the search.

"We also have the assistance of the volunteers, we've also got the assistance of the land councils," she said.

Ms Liddle said there had been "overwhelming" community support and police had "enough volunteers and we have enough specialist people on the ground now to assist us".

However, she added, "we are asking people to ring with any information that they may have".

Asked to respond on Tuesday, Prime Minister Anthony Albanese said it "breaks the heart of everyone who hears about this story. Every parent's worst fear is your child going missing".

"It is of great concern that little Sharon, she's five years old, and she went missing from her home in Alice Springs," he said. "The search is now in its third day. So, our hope is that this ends well."

Assistant Commissioner Malley urged the public to report "any sightings" and any other information they may have.

"Anything, you might think it is small, but it might mean something to us, so please make contact," he said.

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.