Microsoft's open-source file format has been approved by one international standards body, and now is being fast tracked through the another for general approval.

The ECMA (formerly European Computer Manufacturers Association) International standards voted by a count of 20 to 1, with the holdout being IBM, to certify the Office Open XML. It also agreed to propose the format to the International Organization for Standardization, or ISO, for standards approval.

Although the ISO standardisation process can take three quarters of a year, Office Open XML is expected to be fast-tracked through.

The Microsoft open-source standard is rivalled by OpenOffice's OpenDocument Format, or ODT file. However, Novell, who develops the OpenOffice suite of free software, plans to include the Open XML format in its applications, as does Corel, the developer of the WordPerfect Office suite.

Open XML will be the default format in the new Office 2007 suite.