A passerby who witnessed a high-speed chase has helped nab an alleged Queensland fugitive in the middle of a New South Wales swamp.

The good samaritan picked up two police officers and their dog in his four-wheel drive after the cops’ vehicle was caught in a boggy farm track on the mid-north coast on Wednesday.

The officers had earlier clocked a Ford Festiva travelling at more than 190km/h down the Pacific Highway near Collombatti, north of Kempsey, and chased it through farm gates.

With the driver’s help, police located the compact car bogged and abandoned, and soon afterwards nabbed two slow-moving offenders stuck in a swamp.

“They were wet, tired, cold and pretty much gave up,” Acting Senior Sergeant Tswi Schutte said on Thursday.

“It’s great when the public offers their assistance – in a safe-as-possible way of course.”

Sen Sgt Schutte heaped praise on the officers who arrested the offenders in the swamp and then – despite calls to have them winched out by helicopter – managed to make their way back to firmer land.

“It showed great commitment by the officers. They did a great job,” he said.

The 19-year-old driver of the Ford Festiva was charged with multiple offences and is expected to be eventually extradited to Queensland, where he’s allegedly wanted for car-jacking and robbery offences.

His female passenger, 20, was charged with receiving property stolen outside NSW.

-AAP