Missleadfoot it's not a case of airlines being allowed to base crew here, its a case of them wanting to.
Any company (including airlines) can employ Australian based employees, so long as the employment meets the Australian Industrial Relations standards/ taxation laws.
Other Airlines have based crew in Australia, and still do (mainly tech crew).
Its just the fact that the costs of setting up a cabin crew base here, managing it etc would probably put most airlines off. Take QF for example. If the minimum wage in Thailand was more than Australia, and the cost of renting offices etc was more than Australia ...... QF would not have a Thai Base. Airlines only open up bases for cabin crew in areas where it would be (overall) cheaper/ more efficient than if they hired additional crew in their home port. The costs of putting cabin crew up in a hotel here for a couple of nights + allowances isnt that much!
As Australia is pretty far away from most places, and is not a 'hub' for anywhere (no through-flying) this limits the flying that Australian based crew could do. That offset against the high cost of employing people in Australia, and the industrial relations laws here, would make it unviable for most airlines from other countries to base crew here. Airlines with foreign based cabin crew generally base them in 'Hubs' (SIN, BKK, HKG) places where a lot of that airline's flights go through regularly. That way the crew can be untilised effectively. Also airlines base crew in other countries for Language advantages (Japan etc) so that their customers from certain destinations can have someone onboard who is native in their langauage. Australian customers (generally speaking) can understand most versions of English !!
Tech crew are different. Even though there is a wide range of wages from one airline to another, the salary for tech crew is more 'standard' than cabin crew. Sometimes it is cheaper for an overseas carrier to base Australian tech crew here, as they dont have to pay them for living away from Australia, pay childrens school fees etc. I know CX did it once, AirNiugini did also. Plus tech crew can be hard for some airlines to find (qualifications etc).
Whereas the wage for cabin crew vary hugely from one country to another, and Australia has some of the highest rates of pay for cabin crew. Most airlines can easily fill cabin crew vacancies in their own countries (indeed Emirates, Gulf etc get people flocking from other countries to be cabin crew with them!), as there are no qualifications required to become cabin crew !!
My humble thoughts on the matter only
