IBM is the latest company to join the ranks of firms offering free office software as a challenge to Microsoft’s dominance.

Big Blue's Lotus Symphony suite will include word processing, spreadsheet and presentation software and can be downloaded free of charge.

Microsoft Office already faces competition from Google’s web-based tools, called Google Apps.

IBM is committed to opening desktop applications just as it helped open enterprise computing with Linux, said IBM senior vice president Steve Mills.

"The lifeblood of any organisation is contained in thousands of documents. With the Open Document Format, businesses can unlock their information, making it universally accessible on any platform and on the Web in highly flexible ways,” said Mills.