We know that you might only want to work 2 weeks and apply for a job that states you have to commit to a minimum of 4 months. So you show up, tell the company that of course you will stay for 4 months, and after 2 weeks you decide to not come in anymore and quit. It happens a lot, but remember that first of all, you are ruining it for yourself (as you know you will not get a good reference from this company), but secondly, you also ruin it for your fellow travellers. When companies have this happen many times, do prefer not to hire backpackers anymore.
But of course, if you have a horrible time at a company and you really do not feel good going there daily to work, just have a chat with your employer and find another job. You are only in Australia for a short time and you want to have the time of your life, so being miserable is the last thing you want to do.
You can always be honest and say for example you just arrived and not sure how long you will stay for. And of course, if you already know you cannot commit to 4 months, save yourself (and the company) the time and the energy to go for an interview for a job you probably won't get to start with. But maybe you start working and will like it that much, you might end up staying for 5 months...who knows.
Bring a copy of your CV and maybe if you need to sign up with an agency, make sure you have your TFN, copy of your ID and maybe your white card/RSA details with you as well.
If you have any questions at all about the position (this could be from work uniforms to wages to working hours to lunch breaks or eligibility for a second year visa or anything else), do not hesitate to ask the person you have the interview with. Wait with all of these questions during the interview (unless the interviewer brings it up), as if it is a first interview they might do a second or a third round after this, in which you would be able to ask your questions. If it is a one time interview, do not hesitate and check. You can better know before you start than 3 weeks in the job.
Questions they "might" ask you, so you might as well prepare them. Of course these depend all on the job you are applying for. If you want to be a pick/packer in a warehouse, they questions might be completely different of course.
1) What are your salary expectations?
2) How would your colleagues describe you?
3) What are your strong and weak points?
4) Why did you apply with our company and why do you want to work here?
5) What did and didn't you like about your last job position?
GOOD LUCK AND WE HOPE YOU WILL GET THE JOB OF YOUR DREAMS!!!!