Australia has signed on to Microsoft Corp.'s Government Security Program (GSP), giving the Australian government access to the programming code underlying several versions of the Windows operating system, Microsoft said in a statement Thursday.

Microsoft announced the GSP in January. The program, targeted at central governments and international organizations, allows them to assess the security and integrity of Microsoft software. Austria, China, Finland, Norway, Russia, Taiwan, Turkey, the U.K. and the North Atlantic Treaty Organization (NATO) have already signed up for the GSP.

The GSP is also seen as a move in Microsoft's battle against open-source software, primarily the Linux operating system, edging into government administrations around the globe.

Governments signing up to the security program get free online access to source code and other technical information needed to do security reviews. The GSP covers current versions, service packs and beta releases of Windows 2000, Windows XP and Windows Server 2003 and Windows CE, according to Microsoft. In addition, government IT professionals can visit Microsoft headquarters to review Windows development and meet with Microsoft staff.

However, government users under the GSP are not allowed to make modifications to the code or compile the source code into Windows programs themselves. By contrast, an open-source license does allow access and modification of the source code. Governments in Finland, Germany and Taiwan, among other countries, have adopted open-source software or are looking into doing so.

The Australian agreement was signed with the country's Defence Signals Directorate, which is responsible for information security products and services to the Australian government and defense, Microsoft said.

Microsoft is in talks with several other countries and plans to announce more GSP participants before the end of the year, a company spokeswoman said. When it launched GSP, Microsoft said it had identified about 60 countries that are eligible for the program. Eligibility depends largely on national intellectual property laws.

Microsoft sees the GSP as an important part of its Trustworthy Computing initiative, a focus on secure software announced last year by Bill Gates, the Redmond, Washington, company's chairman.

Microsoft shares Windows code with governments, companies and educational institutions under various programs that are part of its Shared Source Initiative announced in 2001. The GSP is different in that Microsoft sees it as a partnership with a country or international organization and it does not require a country or organization to be a Microsoft customer.