What items am I not allowed to bring into a stadium?

SASREA itself doesn't list specific items. It works in two layers:

1. Prescribed prohibited or restricted objects and substances. The Act leaves the list to be prescribed by regulation, and makes it an offence to take or have any of them inside a stadium or venue or along a route (s20(8), s44(1)(m)): a fine and/or up to 10 years' imprisonment. Peace officers may search for and seize them (s20(2)-(3)).
2. The event's conditions of entry. Every ticket must state the conditions of entry (s19(7)), and breaching a ticket condition or the written conditions of entry is also an offence carrying up to 10 years (s44(1)(l)).

For medium- and high-risk events, the planning committee also sets measures to control prohibited or restricted objects, prohibited substances and tobacco for that event (s16(1)(d)).

So the exact list for your match comes from the regulations and the conditions printed on or linked from your ticket, and can differ between events.