This looks to be the only info out there:

http://auspost.com.au/pdfs/click-and-send-update-19-march-2013.pdf

From 8 April 2013, Click and Send will be modified to reflect the launch of our new range of domestic parcel products

Pricing and international zone changes.

Effective from 8 April 2013, some adjustments will be made to our prices.

For further information on any upcoming changes please phone 1300 662 710.