The Open Document Foundation has created a plug-in that makes Microsoft's Office applications compatible with the Open Document Format (ODF). 

The software will allow organisations to open and save ODF documents, even though Microsoft has stated that it will not support the format.

"The ODF plug-in installs on the file menu as a natural and transparent part of the 'open', 'save' and 'save as' sequences," said ODF founder Gary Edwards on Groklaw. 

"As far as end users and other application add-ons are concerned, the ODF plug-in renders ODF documents as if they were native to Microsoft Office."

The project has been under development for a year, he added, and testing was finished at the end of April.

The software is not currently available to the general public, but will initially be provided to the States of Massachusetts and California, and the EU. 

Completion of the plug-in marks an important twist in the discussion over the competing ODF and Microsoft's Open XML document formats.

ODF backers tout the format as the most open standard available. Because of its openness, any application can access and store any document that complies with the standard.

Documents using a closed standard, however, run the risk of becoming unreadable when the application in which they were crafted becomes obsolete.

Governments and archives have reported that they have trouble accessing data that is over 10 years old.

The State of Massachusetts has been one of the more vocal proponents of open formats, and plans to make ODF support a mandatory requirement for future software purchases.

Microsoft has insisted that it will not support ODF because it believes the standard is lacking in several areas such as accessibility features and compatibility with older version of Microsoft Office.

The vendor's decision could have disqualified it from bidding on contracts mandating support for the open format. But a plug-in such as the one now created by the Open Document Foundation eliminates such objections.