The new rules do not appear to be explicitly stated as of yet. However, from what I have observed, NESA is seeking to limit the scope of early offers to university degrees and/or increase the requirements/overall difficulty of receiving an early offer, the reason being that the status quo is said to potentially undermine the importance of the HSC. For example, one of my students has already received an offer into his chosen degree, and while he is still trying to perform to the best of his abilities in his HSC exams, other students who may be in the same situation may feel that doing their best in their HSC exams is no longer justified, which is something that NESA is not happy about.
You may wish to have a look at the following links for more detail:
New rules introduced to curb early university places
www.skynews.com.au
READING LEVEL: ORANGE
www.kidsnews.com.au