The group, the OpenDocument Format Alliance, was formed to solve the problem of users getting locked out of files when they are using an application other than the one the document was created with.
Google, whose Writely online word processing program supports ODF, joined the roster of 240 ODF Alliance members this week, Marino Marcich, managing director of the ODF, said Tuesday.
Google also unveiled its Google Spreadsheets application last month, but has not said whether that program will support ODF. Company spokespeople did not return calls and e-mails seeking comment.
"Google is a major player obviously and a tremendous boost to the alliance," which launched with just 36 members in March, he said. "It demonstrates the depth and growing support behind the ODF.
Although Microsoft Office document formats are the most widely used, the XML-based OpenDocument Format has emerged as an alternative with backing from IBM, Sun Microsystems and others, as well as high-profile government customers in Massachusetts and Belgium.
"When a company like Google puts its name behind any effort to promote OpenDocument Format it's a sign that it is not just a technology on the move, but one that is arriving very rapidly," said Will Rodger, director of public policy at the Computer and Communications Industry Association (CCIA).
Stephen O'Grady, an analyst at RedMonk, said Google's support could bring a large user base.
"If Google includes ODF support in Google Spreadsheets and finds a role for ODF in Gmail then you're talking about a significant number of users who will be using and creating documents in that format," he said.
Microsoft recently launched the Open XML Translator project so developers can create software that will convert Microsoft Office documents to OpenDocument, so they can be opened and saved in the OpenDocument Format.
