Originally Posted by
number_6
OP is flying UA, so there is no alliance partner airline in Oz to use, and UA has no particular arrangements for their pax.
You can book connecting domestic flights within Australia when connecting to United international services on the one ticket. They have baggage interline services with QF, VA and JQ. Obviously not an option when booking an award flight though.
3 hours sounds reasonable. It's a short walk from international to domestic in Melbourne.