A statement released by the airline this morning claimed six of its 10 planes had been removed from service, however, two further aircraft have been grounded since last month following safety concerns.

"This work will undoubtedly result in some disruption within our network," the statement read.

"Brindabella look forward to restoring scheduled services very shortly and apologise to any of its loyal customers who may have been affected.

"Flights scheduled to operate today and during the course of this weekend have not been affected."

Grave fears are held for the future of the airline after it was ordered to pull six more planes from service amid safety concerns.

The Civil Aviation Safety Authority (CASA) issued the directive yesterday after it emerged several planes within the fleet had not undergone mandatory checks.

The order comes into effect at midnight tonight and appears certain to have consequences for Narrabri and Moree, and potentially even the Tamworth to Brisbane route.

Last month four planes were grounded while maintenance reviews were carried out and only two of those aircraft have returned to service.

CASA spokesman Peter Gibson said: "These aircraft may not be flown until the maintenance reviews are completed and CASA has given approval for their return to service.

"The latest direction ensures that any outstanding maintenance related issues have been addressed on all Brindabella aircraft.

"CASA initially required the reviews on the four Jetstream aircraft after finding Brindabella had overrun engine inspections.

"Since then CASA has identified additional inspection and maintenance overruns, leading to the decision to require the six Jetstream and Metroliner additional aircraft to be reviewed."

The groundings will compound Brindabella's already dire financial position, with local councils understood to be owed significant sums of money.