Question

is it possible to trace a relative in new south wales australia

Answer 1

Also, depending on the dates, the NSW BDM (births deaths and marriges) site is really helpful. You need a little bit of info on them, but yes they can be searched. And Ancestry.com.au has heaps of Australian, NSW and otherwise, records if you're a member.
Good Luck!

Answer 2

Is the relative living or dead? If living, I suggest that you could use the electroal rolls or telephone directories. If deceased you would have to apply to the Registrar General in that state for an extract of the death, marriage or birth certoficates.