Common queation
This is a very common situation. Most of the piston engine pilots in the NT are called either casual pilots or contractors. Mostly it is only the CP, senior base pilot, or manager that are employed full time. It's not a very good situation for anyone, because no-one can be sure it will be viable in the long term, or even in the short term.. That's one reason why you hear so much complaining about poor pay. Often pilots do not get ebough hours (just like stacking shelves eh) to make a decent living, and often operators cannot do charters because they cannot get a pilot.
There is a company in Alice Springs (and probably many others elsewhere) that supplies labour (including pilots) for companies. They claim this is perfectly legal. (It's run by an ex polotician) Some time ago I looked at the contract the pilots signed, and it was similar to the GA pilot's award for casual pilots, except that instead of a minimum daily pay rate of four hours there was an hourly rate for ground time and waiting time. I'm not sure of the insurance arrangements, but I would not expect the operator would be paying for it.
If you are employed by someone they are required to provide super payments, workers comp insurance etc. Airports and others often require operators to have public liability insurance. It's prudent to check if this covers pilots.
This is the reason why many pilots join some sort of professional organisation.like AOPA,GAPAN.AFAP stc. These organisations have this sort of knowledge, but are usually reluctant to spend their members money looking after non members.
You can, of course consult a lawyer, or maybe get info from a govt department.