>>1348101NSW. The best opportunity to find one is if you're on the east coast. There's some work outside of the major cities (Newcastle, Mackay, Rockhampton, and very rarely on the NSW north coast) but it's primarily in Melbourne, Sydney, Gold Coast or Brisbane. Look into the NRMjobs email list, every now and then a position comes up in SA and WA but I'd imagine it'd be hyper competitive. Which state are you in, anyway?
It's a shame the Green Army thing is over, it's a good way to get solid experience but attracted a crapload of dropkicks too. If you've got limited environmental experience, see if there's any local landcare groups you can join, or if there's any national parks/state forests/other significant reserves, see if there's a friends-of group relating to it. Go the extra mile and grab yourself a full Chemcert whilst you're at it, and if you're so inclined and don't already have tertiary experience, consider Conservation & Land Management, Horticulture or any other similar ones.
I'm comfy in my job at the moment (I'm saving to get my shit together to go around the country, anyway) but I'd consider going to TAFE to at least have something.
There's lots of National Parks jobs at times too, but they're in absolutely stupid demand and you only get in if you know someone, or your experience absolutely outweighs someone else's. I put in for a few job, but ultimately my colleague, who's done the job for a year longer than me and has a degree got it in the end.
In all, it's not a bad job, but it's always a temporary affair, nobody stays in bush regen for the long term, because it either exhausts you or you get sick of getting your wrists slashed by lantana, but it's quick and easy money.