FRANKFURT/SEATTLE: Microsoft Corp. has lost a preliminary vote to have its Office Open XML document format approved as an international standard, denting the company's hopes of wider adoption of the standard by public-sector organisations.

The result of the International Organisation for Standardisation (ISO) ballot, announced on Tuesday, was hailed as a victory for open standards by supporters of the rival Open Document Format, who argued the Microsoft format was not open, but a ploy to lock in users.

Microsoft failed to capture a two-thirds majority in the vote to approve the file format as a global standard, but the group will meet in February to hammer out a consensus, allowing the world's largest software maker more time to grab votes.

Microsoft's Office Open XML (OOXML) is the default file-saving format in Microsoft Office 2007, the latest version of its dominant productivity software. The Open Document Format (ODF) has already garnered international standard status from the ISO.

"We believe that the final tally in early 2008 will result in the ratification of Open XML as an ISO standard," said Tom Robertson, general manager of interoperability and standards at Microsoft.

Microsoft argues that its format has higher specifications and is more useful than ODF, while opponents say Open XML's 6,000 pages of code compared with ODF's 860 pages make it complicated and untranslatable into other formats.