I am currently pursuing MBA in AUS(1 more year to go), How can I apply for the international offices of MBB and ATK?

Besides the work permit consideration mentioned by Vlad, I think you also need to make a case for why you are applying to the international office(s). Do you have past experience there? Have you ever lived there? Or any other legit personal reasons (e.g. family, partner)? 

The office you apply to wants to know that if they get you in, you have some commitment to the firm/office. If you get in a total foreign office and realised it is not something for you and wants to leave in a short time, it is neither good for you nor for the company. 

Hi,

Depends on what you mean by international:

• You can apply to the offices you can legally work at (Already have a work permit)
• You can try to apply to the offices that are opened for expats (Dubai, Singapore), but that's not guaranteed
• You can't apply to the office where you don't have a work permit (e.g. US)

Best

You have the highest chance of getting in into the office where MBB recruits for at your University. For example, if they recruit for Australian offices and you apply to the London office your chances are much lower as your competition pool is very different and it is unlikely there will be many alumni from your school there to support your application.

If you want to move to a different location, it is easier to transfer internally once you have worked for a couple of years in an Autralian office of the firm you get into

Best,

Udayan