An employee there told Sydney's Daily Telegraph that security video had shown the vehicle driving in "like normal" before someone got out to fill up.
"He is really short. Look he barely even reaches the window," the service station attendant said.
Later that day police spotted the same vehicle in NSW and gave chase.
However, they reportedly pulled out of their pursuit due to concerns about the driver's age.
The vehicle was later spotted on the side of a road in Grafton, says Inspector Darren Williams from New South Wales Police.
"[The children] locked themselves in the car and police have had to use a baton to get into the vehicle to arrest them," he told the ABC.
Williams said the group had most likely shared the driving. A non-stop trip between Gracemere and Grafton would typically take about 10 hours.
"It's a pretty big journey, and it's a long way for a young person — I suppose a couple of cans of Red Bull and you're likely to do anything.
The vehicle belonged to the father of one of the children.
It is understood not all four children were from the same family.
Police said they would question the children once the parents were present.
To be eligible for a licence in Queensland and NSW you must be 17 or older.