Can you have a water birth at a public hospital? (nepean?)
The short answer is no! They don't have a waterbirth policy.

Can you have the normal drugs, ie gas epidural etc during a water birth?
Epidural = unable to walk, so you can't have an epi and a waterbirth. You'll also be continuously monitoed and your labour and birth will be medically managed after you have an epidural. You can have gas and possibly pethidine with a waterbirth, it just depends how much the peth affects you.

The only place to have a waterbirth is at home with a private / independent midwife. No hospitals in your area support it