Missing boy Anthony "AJ" Elfalak has been found alive after a desperate three-day search, NSW Police have confirmed. 

Anthony, or "AJ", who is autistic and non-verbal, had last been seen at about 11.45am on Friday. 

A widespread search of the family's 650-acre property at Putty, west of Newcastle, had lasted for almost 72 hours and included police, emergency services and volunteers when the miraculous discovery was made. 

"Missing 3-year-old boy Anthony 'AJ' Elfalak has been located a short time ago. He is yet to be assessed by NSW Ambulance paramedics. More info to come," NSW Police posted to Twitter. 

It is understood AJ was found by a rescue helicopter at a creek within the property, several kilometres from the family home. 

Police and family raced on foot to the creek and after several minutes of commotion, police confirmed they had found AJ. 

A widespread search of the family's 650-acre property at Putty, west of Newcastle, had lasted for almost 72 hours when the miraculous discovery was made. Photo / Google 

The circumstances of AJ's disappearance remain at this point a mystery, with several suspicious findings made in connection with the search. 

Before the discovery was confirmed, NSW premier Gladys Berejiklian was asked about the good news at her Covid-19 update in Sydney. 

"I don't know if that's the case, but if it is, I would be absolutely delighted," she said. 

"I mean, I think all of us have been crossing everything to make sure AJ is brought back safely. And if that's the case, it's much-needed good news in otherwise difficult circumstances." 

On Friday, the family had noted seeing a "suspicious" white ute on the property, which was then seized from a property at Bulga – 78km northeast of where Anthony was last seen. 

And just hours before AJ was found on Monday, family friend Alan Hashem told the Today show CCTV footage from around the time of Anthony's disappearance had gone missing. 

Anthony, or "AJ", who is autistic and non-verbal, was last seen at about 11.45am on Friday. Today he was found alive. Photo / NSW Police 

"There's one key factor and this is probably the first time I've actually mentioned this, I installed cameras on that post right there," Hashem said. 

"There's footage missing, unexplained. Days before, days after, but not during the time. 

"You know what's more alarming? We installed it so high you can't tamper with it and we had two mechanisms of storage, cloud storage and physical storage, and there's no data in that timeslot. 

"We provided the user name and password to the police, we provided them the actual original memory card. There's a lot of explaining to do." 

Appearing on Sunrise moments later, he elaborated more on the grim discovery. 

"We did have CCTV footage, I (installed) it myself as a matter of fact, I put it high up, so high in the tree that when the (Fire Brigade) said, 'Let me get the CCTV footage,' we went in there and I can't explain it, the window in which he went missing (is gone)," he said. 

"Probably a much greater, larger window, about four hours, there is footage missing. 

"We do have two mechanisms in which we store it, through cloud-based, which is obviously internet-based, and we have also got the physical memory cards, both have been provided to police and they are investigating further." 

At the time, Hashem said he feared Anthony was abducted. 

"Without a doubt; for the simple reason he is on the spectrum of autism but he is always quite afraid and attached to his mum," he said. 

Family's joy after hearing AJ was found 

News crews at the property captured the moment the family found out he had been located. 

There were emotional scenes at the property as family members threw their hands in the air, screaming and crying from happiness and relief. 

AJ's father hugging his other two children after hearing his son had been found. Photo / 9 News 

"Thank you for everyone. Thank you for the government. Thank you for the police. Thank you very much," AJ's mum Kelly told Nine News. 

"Thank you to my friend, my cousin, my sisters, my family. Thank you, everybody and whoever prayed for us." 

Alan Hashem, AJ's godfather, said they still had no answers on how he disappeared. 

"I know I was acting frantic, but no one can understand what it's like going through what we went through. I feel incredible, mate," he said. 

"All that noise just disappears. But we still need to find out what happened. We need answers. This is our little fortress. How did he leave? Who did he leave with? Did anything sinister happen? You know, these are questions that need to still be answered. 

"We will not stop until we actually find the truth." 

NSW Ambulance paramedics have made their way to the boy, who reportedly has some light scratches on his body.