Microsoft Corp. is updating its online corporate software offerings to include a full Internet-based version of Office 2010 for the first time, an effort to stave off competition from Google Inc. for business accounts.

The Office 365 suite of programs will be introduced today at an event in New York with Chief Executive Officer Steve Ballmer. The software will cost small businesses $6 a user each month for a package with programs like Office Web Apps and Exchange e-mail software, Microsoft said. For an additional $12 a month, companies can add a full version of Office, including Word and Excel programs.

Microsoft, based in Redmond, Washington, is trying to keep Google's office-productivity software, called Apps for Business, from making further inroads with corporate and government clients. The two companies are fighting for customers who want more applications hosted in the so-called cloud — on a network rather than a hard drive. The full online version of Office follows last year's release of the more basic Office Web Apps.