Citing "performance issues", Microsoft said last week that it will not release Office 2007 to enterprises until "the end of 2006". The consumer launch will take place some time in "early 2007".
But David Bradshaw, an analyst with Ovum, said: "It seems sensible to keep Office 2007 in step with Vista, and Vista is already delayed, so this is not entirely surprising to us.
"There is wide speculation that Vista will be delayed again, and this would be an embarrassment for Microsoft.
"Vista is a much more ambitious project than Office 2007, and has already seen several delays. Microsoft may face the same decision again: whether to postpone Office 2007 or launch it without Vista."
The analyst suggested that delaying Office 2007 will have a minimal impact on Microsoft's product revenues as most customers will buy Office only when they need it, for example when they upgrade to new computers.
The rescheduling marks the second delay to Office 2007 this year. Microsoft said in March that it would hold back the release to coincide with the launch of Windows Vista.