11/8/2016 8:58 AM
Edited Date/Time: 11/8/2016 9:07 AM
Hey dude, i'm from Australia too. Check out these following sites, LUXBMX, BackBoneBmx, StrictlyBmx, ChainReactionCycles. All these sites are great and safe 
This bike is amazing for its price, full chromo, double walled rims, 4 pegs and 3 guards! (Would need another rear guard to grind on both sides without messing up your hub)
http://www.chainreactioncycles.com/au/en/division-fortiz-bmx-bike-2016/rp-prod145833
The only thing about this bike is that it does not have brake mounts so you would not have brakes and you would have to jam your foot in the back tire to stop... Probably not a good idea for a beginner though :/ I would highly recommend brakes for a beginner.
Look for a FULL chromoly frame, forks, bars, cranks, double walled rims, sealed bearings all round, female front axle.
If you price range is about 600AUD and you are wanting to get into bmx and not worry about messing around with parts and swapping them out too soon then i would spend a bit extra to get the good stuff!
If you need more help dont be afraid to ask on here 