The star parties in SEQld that I know of always welcome new comers. These are Cambroon 140 kms north of Brisbane and Leyburn 210 kms south-west of Brisbane. There is usually up to 25 people attending during the nearest to New Moon weekends.
The Cambroon events are announced here on this forum in the star parties sub-forum:
http://www.iceinspace.com.au/forum/s...ad.php?t=18645
The Leyburn events can be found on the web page of the Southern Astronomical Society.
I can't speak for Illford in NSW (used by the Astronomical Society of NSW) or the Leon Mow dark sky site outside Heathcote Victoria used by the Astronomical Society of Victoria, but both would have events close to New Moon. I don't know how welcome vistors who are not members are.
Where are you landing in Aust? What is your intinery?