The specification for Office Open XML (OOXML) has finally been published by the International Organisation for Standardisation (ISO).

The documentation for Office Open XML (OOXML) runs to 7,228 pages and can be ordered on CD from the ISO for 342 Swiss francs (£189). The specification is named ISO/IEC DIS 29500:2008.

Microsoft, which created the file format, won a hard-fought battle in April when the ISO announced enough countries voted to approve OOXML as an international standard.

OOXML was opposed by many on grounds it was unneeded, as software makers could use OpenDocument Format (ODF), a less complicated office software format that was already an international standard.

The debate became so embittered that IBM, which backs ODF, threatened in September to consider leaving standards bodies that allowed dominant companies such as Microsoft to wield what it perceived as undue influence. Microsoft was accused of leaning on countries in order to secure enough votes for OOXML to pass.

OOXML's publication means software developers can begin implementing the specifications into their products for free. Some developers have already used parts of OOXML in their products, mostly to operate better with other Microsoft software.

Microsoft uses a version of OOXML in its Office 2007 productivity suite. Company officials have indicated that future software products would adhere to the ISO-approved OOXML specification.

The ISO said the specification "is intended to be implemented by multiple applications on multiple platforms".