A best it's a very grey area. You have foreigners working for an Australian company within Australia, possibly without the correct visa.
There are many kinds of visas available for different purposes of entry. A multi national might send down a specialist to oversee the establishment of a new subsidiary, an overseas trainer may be hired to teach staff how to use new equipment. These people would need to apply for appropriate permits and most likely they would be granted.
Try telling immigration you want to bring in fifty unskilled workers because they will work for a third of what an Australian would cost and see what kind of response you would get.
I've had my name on hundreds of General Declarations and I don't remember one which gave me the right to work for a local company in the country I was transiting.
Could an American working for COCA COLA in the USA come to Australia and start loading trucks with pallets of COKE ?
What about income tax ? Can I work in Australia for a local company and be paid abroad and taxed at much lower rates ?
Workers comp ? What if a Singapore F/A falls off a VH reg aircraft while working in MEL ?
Having foreigners working on Australian registered aircraft on domestic sectors raises alot of questions. Prehaps someone from Immigration could provide answers ?
PS See similar thread
http://www.pprune.org/dg-p-reporting...-widebody.html