Google has added the StarOffice set of programmes to its Google Pack, a free collection of recommended software downloads.

The move is another challenge to Microsoft's domination of the office suite format, with Google already offering its own word processing and spreadsheet systems online.

"We partnered with Sun to make a free version of StarOffice available in the Google Pack because we believe that users will benefit from access to a free, full-featured office suite for the desktop, " Google said in a statement

"And we’ve also always believed that users should have choice in their online and PC experience."

StarOffice usually costs $70 (£35) but is free as part of the latest version of the Google Pack.

Although details of the deal haven't been officially announced, Google is thought to be paying its creator Sun to distribute the software for free.

StarOffice may eventually be supported by embedding adverts into the software.

Sun and Google originally partnered to tie their products closer together back in October 2005.

The inclusion of StarOffice in the Google Pack has sparked internet rumours that Google's own Docs and Spreadsheets service will be integrated to work with office suite.