Microsoft Corp. has failed to win approval of its Office file format as the international standard, a potentially costly defeat as governments move to open formats and away from those controlled by one particular software company.

The International Organization for Standardization (ISO), which sets specifications on a host of matters including computer codes, rejected Microsoft's application to ratify its Open XML file format as an international standard. 

Attaining the standard would have been advantageous for Microsoft, which is looking to gain business from governments by dispelling suspicions of monopolistic practices. Governments, which generate millions of everyday documents such as spreadsheets and word-processor files, are also looking to move away from Microsoft over concerns that they could be forever beholden to the company.

The struggle over standards has pitted Microsoft against companies such as International Business Machines Corp. and Sun Microsystems Inc., which have argued the company prevents rivals from developing competing office software. Microsoft's move to standardization is an attempt to defuse those concerns, but the formats — if ratified — would still be largely controlled by the company, they said.

Microsoft has said its move to a more open Office format is an attempt to spur competition, not limit it.

Although the ISO has not yet commented on the ruling, a number of countries have criticized Microsoft's application. Brazil raised more than 60 objections, while the French Association for Standardization said it would like to split Microsoft's proposal into two parts. One part would deal with making Microsoft's formats compatible with the already standardized open document format, used by IBM and many open-source programmers, while the other would deal with the company's older documents.

The ISO defeat was a narrow one, with 74 per cent of voting countries in favour of adopting Open XML as the standard. A Microsoft spokesperson said the company was "extremely delighted" with the result despite the defeat, given that it was just shy of the 75 per cent needed for ratification. The company will try to address criticisms of its format and try again with another vote early next year.

The company also missed out on a second count, however, in that more than two-thirds of a key group of voting countries had to approve the application. Only 53 per cent of these countries voted in favour.

Microsoft had previously won standardization for Open XML from Ecma International, an association of computer industry manufacturers.