Representatives from the airline will not say when they expect the service to start again, but in a statement said it would be reviewed when the "reliability and integrity" of scheduled services is restored.

"Brindabella was pleased with the inroads made in winning customers on the Sydney to Orange route, and would like to thank those customers for their patronage," the statement said. 

Passengers with existing bookings on Brindabella's services between Sydney and Orange will be contacted and offered full refunds without cancellation penalties.

The suspension comes less than a week since the Civil Aviation Safety Authority (CASA) grounded four of the airline's planes after the airline admitted routine engine inspections were overdue.

Only two of the planes have been given the OK to return to the skies so far.

More details in Saturday's Central Western Daily

.