You have to be licenced under a non-indigenous animal permit (or and exhibitors permit) issued by the nsw dpi, they assess them on a case by case basis, I know of 5 other private keepers in nsw with crocs and all have similiar qualifications, your very bare minimum is a certificate 3 in captive animal management, you then need to prove at least 12 months experience in working with or around crocs (they ask for experience working with neonates to the giants) and have at least 2 references to say you have what it takes (mine came from some big names). You need to prove your enclosure will be secure and comply with dpi rules and regs and you need to provide a plan of what will come of the animal when it gets bigger or should something happen to you (mine goes back to reptile park in the event i can no longer care for him). The dpi have sadly in recent years become less willing to grant class 3a and 3b permits to private holders but its still possible if you put the effort in. Its not a cheap investment though, for licence your looking at $80 a year and enclosures run around the $3000 mark, plus you need your certificates and be prepared to kiss a while lot of ***
I will upload some pics later on of my little guy for you guys to take a look at