It depends what course you want to transfer in, and which uni you want to transfer to. Certain universities have mid year entry for certain courses. Check the UAC site around April for more information.
Hello, I emailed UNSW regarding transferring last week, this is what they said
UNSW said:
You will need to complete a minimum of 0.75 of a full time year in a single degree program at UWS in order for your tertiary results to be taken into consideration. Having completed one full time year (or 0.75) you will be assessed for admission on the basis of your first year results or your ATAR, UNSW will consider the better of the two.