I'm ignorant as far as Australian law. Is this true if the company is based in America and the worker is laboring either in America or remotely? It seems like at that point Australian law wouldn't directly apply to termination decisions.
Generally speaking, multinational companies will offer employment contracts through a local subsidiary. In that case the employment will fall under the laws of that country. And if they send you on an overseas business trip that doesn't change anything - even if the parent company is domiciled in that country.
If they don't have a local presence, and you're working remotely, then you're more likely to be a contractor and dismissal laws are pretty loose.
The interesting thing would be if they had a local subsidiary but chose to employ you on contract to the parent company. I suspect (but IANAL) that the Australian Fair Work Commission would determine that (if the contract was long term and indefinite) that you were actually an employee of the local subsidiary.
