I suspect, "Not as many as you think" because prescription sales will move on-line with lower prices and higher competition.
Australia Post will be leading a part of the Internet Shopping Revolution: physical delivery. They are providing secure "parcel lockers" accessible at any time. 
The Internet, as "bits and clicks", does browsing, shopping, payment and central fulfilment well, but the last link in the logistics chain, customer delivery, is weak. Secure, convenient, fast parcel delivery addresses this weakness. Can we assume that their courier service can access the lockers as well? 
Not mentioned is real-time tracking for parcels and packages.  If the organisation has the technology and customer demand, it should show up sooner, rather than later.
From this start, it is only a very short step to automated on-line dispensing from the GP's office. 
The PCEHR  already foreshadows exactly this as something useful, exciting and cheap.
Which implies that GP's, or more accurately the super-clinics that employ them, will be linked to a single, central automatic dispensing pharmacy. The high capital investment, employee productivity gains and high-turnover/thin margins mean there will be a limited number of these services. Nor, it would seem, room for many pharmacists when order fulfilment is fully automatic. A degree needed just to load the robots? Management will look to remove that "expensive" requirement.
The impact on Community Pharmacies will be twofold: either become a small drop-off/collection point similar to those of Pathology Services or discover niche markets and services that must be delivered locally and in person.
For anyone who's been caught in the rush and inattention of our increasingly "Factory Farmed" GP services, you'll be aware of the gaping hole in this nerdtopia vision of "direct from GP to you, never touched by human hand or mind": Who do you get sanity checks, advice and on-going monitoring from?
GP's, well intentioned as they are, are time-poor, distracted and not experts in drug interactions, nor simple supplementary remedies/treatments and nutrition: all the things that are the preserve and expert domain of Pharmacists.
Medicare will need to recognise the role for, and necessity of, Consulting Community Pharmacists. Small pharmacies cannot wear the cost and patients cannot be expected to pay the full cost.
Who will catch inadvertent mistakes by GP's, answers patient questions or emphasise dangers or requirements of taking medications ("with a meal", "no alcohol", "take the whole course")? This is part of the role of Hospital Pharmacists and in a fully automatic world, there will be nobody responsible, or able, to catch these errors.
Medication errors in the community, leading to injury and death, are already a growing problem.
The Brave New World, envisioned by NETA/PCEHR, based on mindless electronic efficiency will accidentally solve the economic problems of an ageing population: Almost nobody will survive past age 75 due to unmonitored medications and undetected errors and interactions.
This technology challenge to a "traditional bricks-and-mortar" model is not unheralded: Newspapers who ignored the threat of Internet Advertising since 1998 have successively closed their doors. 
 Australia Post increases profit by 16.6 per cent to $281 million - announces $2 Billion investment to transform Australia Post [media release]
- Lost $148MM on 'letters' in 2012.
- made $546MM on parcels, couriers and retail business.
- doing "digital"
- investing $2B over 4 years, including a "storage locker" system for parcel delivery. When parcel arrives from an Internet retailer and if you've registered your details, you get an SMS or email. Most people collect within 6 hours.
Continued investment in 24/7 parcel lockers and retail superstores will also mean that by 2014, 80 per cent of Australians in metropolitan areas will be within 10 minutes drive of an after-hours parcel collection location.On-line sales are still doubling every 3-4 years, this change has a long way to run. More from the media release:
Online shopping continues to grow in Australia, with local consumers spending a total of $11.9 billion in online retail sales in the last year - an increase of around 22 per cent, year on year. In good news for local e-tailers, more than 70 per cent of these items are purchased through local online retailers.There is a challenge to be addressed: controlled temperature packaging.
Australia Post specifically says the lockers are not for perishable products.
The NGO's that ship vacines around Africa have simple, unpowered "cool packs" - evaporative cooling. They will keep the contents cool for many days (a week?). Exactly right for Australia and closed trucks in its harsh summers.
 Parcel Lockers
 Australia Post buys remainder of StarTrack couriers from Qantas.
 StarTrack real-time package tracking
 Meditec Australia Medication Packer
 McKesson Hospital Pharmacy Automation
 Personally Controlled Electronic Healthcare Records (PCEHR), E-health and medications.
 Saving the Masthead. The story of Fairfax destroying its "rivers of gold".