In a drive to improve interoperability, Microsoft has said it will offer greater choice and flexibility among its document formats.

The release of Microsoft Office 2007 Service Pack 2, scheduled for the first half of 2009, will expand the list to include support for XML Paper Specification, Portable Document Format and Open Document Format (ODF).

The announcement is in line with the company's principles around interoperability, said Chris Capossela, senior vice president for the Microsoft Business Division.

“We are committed to providing Office users with greater choice among document formats and enhanced interoperability between those formats and the applications that implement them,” he said.

“By increasing the openness of our products and participating actively in the development and maintenance of document format standards, we believe we can help create opportunities for developers and competitors, including members of the open source communities, to innovate and deliver new value for customers.”

However, sceptics are concerned about the extent to which Microsoft will be open about how far its policy of openness will stretch.

Marino Marcich, managing director of the ODF Alliance, said: "The proof will be whether and when Microsoft's promised support for ODF is on par with its support for its own formats. Microsoft has a long history of broken promises, so no one should celebrate this news until we see what is actually done and how quickly it is put in place.

"Governments will be looking for actual results, not promises in press releases."