A man who allegedly abducted a 12-year-old boy from outside his Gold Coast home is likely to be charged with kidnapping for ransom, police say.

An amber alert was issued on Friday night, hours after the boy was pulled into a car outside his home at Mudgeeraba about 3:30pm.

He was found at about 12:00pm on Saturday some 240 kilometres away in Grafton, NSW, after a member of the public called police having seen the dark blue 2013 Jeep Compass mentioned in the amber alert.

The boy was found inside the car, along with a 53-year-old man, who is now in custody.

Speaking at a press conference on Saturday afternoon, detective Inspector Marc Hogan said police would apply for the man's extradition on Monday.

"We will be looking to charge the male person on his return to Queensland with [a] kidnapping for ransom offence," he said.

The ABC understands the 53-year-old is NSW-based, of Chinese heritage and not related to the boy but known to the family.

It is believed detectives are investigating whether the alleged extortion attempt was related to gambling debts.

"It's the case that both parties were known to each other and there were financial issues involved in the lead-up to the abduction of the child."

Detective Inspector Hogan said it was in relation to "personal loans".

"In the lead-up to the abduction requests were made for money and of course that sort of led us pretty quickly to identifying who we should be looking at," he said.

Detective Inspector Hogan said police were also investigating the possibility of other people being involved.

Boy treated for scratches 'consistent with being bound'

The boy's family arrived in Grafton on Saturday and were reunited with him at the police station.

Earlier he was treated for scratches "consistent with being bound".

"He had some slight scratches consistent with being bound. As a precaution … the boy was taken to the hospital just for an examination," Detective Inspector Hogan said.

He said they managed to track the vehicle using traffic cameras.

"NSW Police put up a number of staging points along the highway, and just through a matter of trial and error we narrowed it down to a certain area," he said.

"A member of the public recognised the vehicle, called it into police, and the boy was located in the vehicle with the male person."

Detective Inspector Hogan said police waited several hours on Friday before alerting the public about the missing boy because they believed it could have been resolved.

He thanked the media, the public, and NSW police for their assistance.