Keep a notebook of new terms. Different lecturers have different pronunciation. Yes, they do. Once you have decided that it is the lecturer's pronunciation, and not your lack of knowledge, that is creating a difficulty, you might be able to discover where he or she comes from and find out the characteristics of speech from that part of the world. You won't be able to change the way the lecturer speaks, but you might get to understand him or her better.
Some lecturers use strange idioms.
Yes, this can make it very difficult for non-native speakers to understand. You can widen your knowledge of idiomatic English by chatting with Australians as often as possible and by watching Australian TV programs. I don't have enough cultural background knowledge about Australia. It is often difficult for lecturers to remember that students who have not been in Australia for long have a pool of general knowledge very different from Australian students. Remember that one friendly and helpful place to ask questions is the Academic Skills Program .