Over the last few years I have linked to various national government policies on Open Source software and procurement policies. But I see I omitted us in Australia. So here is what I can find, from 2005: Guide to Open Source Software for Australian Government Agencies
Of interest, in the section Preparing a procurement plan: Procurement Scenarios is:
Increasing longevity of document accessibility
In this example, an agency has a business objective to maintain long-term access to its electronic documents. The agency may mandate the adoption of open standards formats to be used for the long-term archiving of documents. This mandate may be defensible if the specific requirement is defined as: "We want to ensure we can retrieve all archived documents in the medium to long term." A document format based on open standards is selected for this purpose. If an open source solution can be shown to implement the standards-based document format, then it can potentially deliver the mandatory outcome. The OSS-based solution can therefore be considered for procurement.
Any readers with updates on this (has there been no progress in 5 years?) please feel free to add a link in a comment!