Hi
I know you didn't include the west coast in your query (Perth) but I can
assure you we have a weekly session here in a pub (Davilak Hotel, South
Fremantle). Not a very high standard  but there are a few really good
musicians in town as well that turn up now and again. As for the East coast,
Melbourne has probably the biggest Irish music scene with Sydney and
Brisbane following. I can put you in touch with the Sydney crowd and point
you inthe right direction as far as Melbourne is concerned.
Happy to help further if you want to PM me
Cheers
Donough