Car horns tooted, family members laughed, danced and cried as members of the search party returned to the home after confirmation the boy was alive and well.

Father Anthony Elfalak said it was "a miracle".

"I've been in the bush for four days, no sleep," he said. "We didn't stop."

Asked what kept him going, Mr Elfalak replied: "Just finding my son, he's named after me, he's my baby boy".

Mr Eflalak said his son was found about 500m from the house - in an area they had previously searched.

After being spotted by a helicopter, he was found drinking water from the creek.

"I want to thank everyone," Mr Elfalak said after being asked about the search which included 130 emergency personnel.

"I've never seen anything like it. We never gave up hope."

Mr Elfalak said his son had nappy rash and some scratches on his hands from where had fallen over but otherwise seemed OK.

He was to be taken to Singleton hospital.

"There's going to be some celebrating tonight," he said.

EARLIER: Anthony "AJ" Elfalak has been found alive near a creek three days after his disappearance.

It is understood a rescue helicopter spotted the three-year-old several kilometres from the family home on Monday morning.

He is being assessed by paramedics and is expected to be transferred to Singleton Hospital.

AJ's mother, Kelly Elfalak, fell to her knees as police told her they had found her son.

"Thank you everyone, thanks God, thank you for whoever prayed for us. Thank you for everyone who supported us," she said.

AJ, who has non-verbal autism, went missing on Friday from his family's rural property at Putty.

More than 130 people were involved in the around-the-clock search of the 263-hectare property.

Police seized a white ute on Sunday night and checked an abandoned property nearby after his family raised concerns that he may have been kidnapped.

A family friend also claimed that critical CCTV footage from the time AJ was last seen had vanished from the family's cameras.

Premier Gladys Berejiklian said she was "delighted" to hear the good news at her COVID-19 update in Sydney.

"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 a much-needed good news in otherwise difficult circumstances," she said.