There's a list of the required subjects, I suppose you can do a search on the handbook (http://www.handbook.unsw.edu.au/vbook2006/quickResults.jsp) for each subject required so you can get a jist of what subjects you'll have to do. But by looking at the names of the list there is a concetration of heavy maths subjects you can optionally do. Just like business law can steer clear of tax law subjects (as they're optional).