i got the paperwork on this at booking appt last week - basically, they test for several disorders and "diagnose" around 54 cases (on average) each year in Victoria - this is from approx 62000 babies born

the main tested disorders are:
Phenylketonuria (~5 per year)
Congenital Hypothyroidism (~20 per year)
Cystic Fibroses (~20 per year)
Other rare metabolic disorders (~9 per year)

according to the handout we received, the sample cards are kept on file indefinitely, but identifying information is only used with the prior permission of the parents - so like Kate mentioned, there may be random samples used for testing for research, but if any identifying information is to be used, the parents have to agree to it....