The five-year-old was last seen when she was put to bed late on Saturday.
Police are today continuing the search for a 47-year-old man who had recently been released from prison over the suspected abduction of a young girl in the Northern Territory.
Five-year-old Sharon was reported missing about 1.30am on Sunday from her home in Old Timers Camp on Marshall Court in Alice Springs.
She had been put to bed about 11.30pm on Saturday before she was later noticed to be missing.
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The search - now in its third day - involves foot searches, drones and helicopters.
Acting Commissioner Peter Malley said there was a party at the house where Sharon was put to bed on Saturday night, but that he didn't know how many people were there.
He added Lewis only had a "loose connection to the family."
"They just happened to be present together at that location on Saturday night," he said.
Lewis was last seen holding hands with a young child after 11pm on Saturday.
Malley said police believe she is still alive, but admits it is paramount that Sharon is found soon.
"As time goes on, the chances of finding her alive and well, reduce," he said, rejecting suggestions the search started too late.
"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."
Acting Commander Mark Grieve confirmed yesterday that police are asking for public assistance to find Jefferson Lewis, who was in the area at the time and staying at the residence, and who is believed to have disappeared around the same time.
"We do believe Sharon has been abducted, and we believe Mr Jefferson may be able to provide us with some information in regards to this," Grieve said.
"He currently remains one of the few people who were in Old Timers Camp at the time and has not made themselves known to police, nor have police been able to locate him at this point in time."
He said Lewis had recently been released from prison, after being jailed for violent offences including assault and domestic violence.
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"We're still trying to work through his movements since he got out of prison, we certainly know that he was in and around Old Timers Camp at that particular residence Saturday afternoon and into that evening."
Grieve could not confirm how many people were at the home but said he understood Sharon's mother and other family were present.
Lewis is not directly related to Sharon, but is believed to have been known to the family, Grieve said.
"It's a terrible situation to have such a young child go missing, we're over 24 hours now so it would certainly be my worst nightmare as a parent," Grieve said.
He said police were "wrapping around" Sharon's mother and had provided accommodation and support to the family.
"We want to find Sharon healthy and we want to get her back to her family."
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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, and a pair of black boxer-style underwear.
Police don't believe Lewis has access to a vehicle, but concede he may have someone assisting him.
Police believe he is still within a 20km radius of where Sharon went missing, and don't believe he has gone interstate.
The Northern Territory Major Crime Squad travelled to the home yesterday, and confirmed they spoke with multiple people who were there on Saturday night.
Anyone with information should call 131 444.
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