A bus carrying schoolchildren and members of the public has crashed down an embankment in the NSW Riverina.

A number of passengers became trapped when the bus crashed near the Demondrille Creek Bridge at Harden.

Ambulance Superintendent Mark Gibbs says more than a dozen passengers were transported to Harden hospital for an assessment.

Two passengers are critically injured and have been airlifted from the scene, including a 65-year-old woman with head injuries and an 8-year-old male with fractures.

The cause of the crash is not yet known.

#UPDATE: Two patients have been airlifted to The Canberra Hospital. Paramedics are attending The Harden Hospital to assist doctors in treating patients and potentially transporting them for further assessment #nswambulance #harden pic.twitter.com/Y09o6Zru4y

— NSW Ambulance (@NSWAmbulance) September 27, 2019

There were six people trapped on the bus when first responders arrived at the scene.

“It was quite a chaotic scene of people running around everywhere,” said NSW Ambulance Superintendent Mark Gibbs.

“The bus had run off the embankment, down into the creek, off a very narrow bridge,” he told Karl Stefanovic.

“It was up on its wheels, so it would’ve been a very confronting ride for the children and the adults.”

He explained that the ambulance crew were well-equipped to care for the injured passengers, saying “this is their bread and butter”, and all the emergency services worked together to get the patients to safety.

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