More leaks have emerged from the tight cocoon of self-imposed silence surrounding Microsoft CEO Steve Ballmer"s activities in Australia, with three Cabinet ministers including Treasurer Peter Costello now confirmed to have met Ballmer for discussions in Sydney on Monday.

While the Treasurer"s office is keeping quiet about what was discussed between the two heavyweight deputies, The Australian Taxation Office (part of Treasury) recently endured trenchant criticism after electing to remain on Windows for its desktop front end of choice as part of a major technology program called the Change Program.

It appears also Mr. Ballmer may have had more success than first conveyed by his secretive team in terms of getting his foot into the door of other Australian leaders.

The CEO of the A$270-billion software corporation has also held meetings with Health Minister Tony Abbott and Communications Minister Helen Coonan, although the subject matter of the talks is still officially off limits, with staff simply saying the meetings were not public.

Ballmer apparently expressed his belief that demand from IT consumers is necessary to support IT manufacturing and service industries to Coonan, as well opportunities for Australia to become a producer of digital content.

Meanwhile a whitepaper on interoperability circulated by Microsoft to policy makers has set tongues wagging in the open source community. The 1600-word treatise on e-government and interoperability is provided in MS Word format -- a point seized upon by Linux devotees who allege graphics and tables in the document will simply not load for users of open-source operating systems.

Mr Ballmer left Australia for China on Tuesday.