Four children in Australia got into one of their parents' car and drove for more than 900km before being stopped by police the next day.

The three boys and a girl - all aged 10-14 - were discovered safe in the New South Wales town of Grafton on Sunday (Jul 14), the BBC reports.

They had left Gracemere, in Queensland, sometime earlier in the weekend. One boy reportedly wrote a note to his family to say he was leaving.

Police said they would lay charges, but did not specify which ones.

The children were not all from the same family and had stolen the 4x4 from one of their parents, authorities said.

Early on Sunday, about 140km into their journey, the group stopped at a service station in and allegedly stole petrol.

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 vehicle in Glen Innes - a town near Grafton - and began pursuing it. However, officers stopped the chase due to concerns about the driver's age.

The vehicle was later spotted on the side of a road in Grafton, according to 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 said, reported the Australian Broadcasting Corporation.

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," he said.

Police said they would question the children once their parents were present.

Motorists must be aged 17 or older to be eligible for a licence in Queensland and New South Wales.