Microsoft Corp. will delay the release of Office 2008 for Apple Inc.'s Macintosh computers until the middle of January to fix bugs in the software.

"It really is just a quality issue across the board," Craig Eisler, general manager of Microsoft's Macintosh business unit, said in an interview Wednesday.

Eisler said Apple's decision to switch to Intel-based chips disrupted the software development process, as did Microsoft's move to a new file format with the release of Office 2007 for Windows-based computers.

Microsoft is now aiming to launch the software at the Macworld mega-conference for all things Apple in mid-January, and it will be widely available in the first quarter. Eisler did not say how much the suite will cost. Office 2004 for Macs costs between $150 and $500 on Apple's website, depending on the version. The release was originally scheduled for December.

The setback is similar to the delays for Microsoft's newest operating system, Windows Vista, and the Office 2007 programs for Windows-based computers, which finally reached consumers in January of this year.

Windows PC users far outnumber Mac users, but Apple's market share is growing, and with them, U.S. retail sales of Office for Macintosh, according to the market data researchers NPD Group.

Sales of Office for Macs rose about 72 per cent from 2001 to 2006, compared to an increase of about 18 per cent for Windows versions. Sales of the Mac versions made up about 20 per cent of dollars spent on Office at U.S. retail stores and websites in 2006, up from four per cent in 2001.

"Even though Microsoft is losing that operating system sale, they're still keeping that Office sale," noted Chris Swenson, an NPD analyst.

Swenson said the low cost of the version meant for student and home use, which makes up about 80 per cent of Office copies shipped to retailers, makes buying the software "a no-brainer" for consumers.

"It's not a total loss, switching to the Mac," he said.