You wouldn't be able to start work without at least a Work Permit or, as Amy says, a WHV which allows you to work for a certain period. In your case it's not worth suggesting you go on a Visitor's Visa, like we do for other people, as you can't work on that.

You're no doubt going to run into problems time-wise due to the Christmas and New Year shutdown. Pity about the timing. :(

Hope you can sort something out as you're obviously very keen to get there and get started. Usually, if you have a job offer, they're very keen to get you there so PR should be pretty quick although your registration (or lack of it) could well put a spanner in the works. :-/