The majority of students were given a middle ear test, while those suspected of having permanent hearing damage underwent a bone conduction test to assess their choclear.

Learning and Support Teacher Kirstie Jackson, who was also tested, said with public Ear, Nose and Throat (ENT) specialists having such long waiting lists, the bus plays an important role in the early detection of hearing problems.

"The ENT's have an 11-month waiting list. That's a year of learning those kids are missing out on," Ms Jackson said.

It's an issue close to Ms Jackson's heart.

On the day before her second birthday, Ms Jackson's daughter Ruby was found to have severe glue ear, a build-up of fluid inside the middle ear cavity.

Within two weeks, Ruby underwent surgery to have grommets in her ears to drain out the fluid and allow air to pass in and out of the ear.

Ms Jackson said the change in her daughter's hearing and speech was remarkable.

Two years later, Ruby, who is now four-years-old, was tested alongside the school students and her mum said she passed with flying colours. Dubbo South Public School recently raised $1000 for the Hear Our Heart Bus by collecting 5c pieces.