I don't know it is different in every port. Most places check in and customer srvice staff are Jetstar employees. I think the Turn Around Co ordinators are too.
Then main ports have Express Ground Handling (another QF company) for ramp operations. Gold Coast, Launceston and Hobart are all QF Staff although I heard they are contractors to QF. I thought they were QF employess though. How knows?
The Qantas Group is just one HUGE mess of shelf companies, subsideries, accounting divisions and contractors!