Hope this helps:

The Australian Government provides a basic universal health insurance, Medicare. Private health insurance in Australia is limited to those services not covered by Medicare or to services provided in private hospitals.
http://en.wikipedia.org/wiki/Insurance_in_Australia

The Pharmaceutical Benefits Scheme (PBS) is one of four arms of the National Medicinal Drug Policy [1]. The main purpose of the PBS is to provide timely and reliable access to appropriate and cost effective prescription medicines to the Australian community at the lowest cost to the Government and consumers.
http://www.psa.org.au/site.php?id=640

(Australian) Federal Government Rebate
What is the Federal Government Rebate?
The Federal Government 30% Rebate on private health insurance makes health cover more affordable for eligible members by reducing premiums.
The rebate levels are:
* 30% off your premium for those aged 64 or under.
* 35% off your premium for those aged 65-69.
* 40% off your premium for those aged 70 or more.
You can claim the 35% or 40% rebates on your entire membership as soon as at least one member fits into either of the relevant age categories.
Members can get the rebate in one of three ways:
1. An automatic reduction in premiums - you can register to receive the rebate as a reduction in premiums when you join online.
2. Claim your rebate from Medicare - Medibank Private can provide you with a receipt for the premiums you have paid and then you can claim your rebate from any Medicare office.
3. Claim in your tax return -when completing your tax return, refer to the Private Health Insurance Statement we send you each year. This tells you the rebate amount you are eligible to claim.
http://www.medibank.com.au/Health-Covers/About-Health-Insura...