As far as I know it can be done with a local sim card as you can certainly sms. Can you arrange for people to call you back from Australia landline to Bali landline? It seems to be cheaper if you call to Bali than from Bali. Also, could you purchase a phone card in Bali? I use one here to call to Bali and it's very economical. Any mobile calls seem to be very expensive.

Catherine