SEATTLE -- A top Microsoft executive side-stepped questions on Tuesday about any plans the software maker may have to bring its Office suite of applications to Apple's (AAPL) iPad.

Talk has circulated for more than a year that Microsoft wants to bring native versions of its most profitable product to the hot-selling iPad, which one analyst estimates could generate $2.5 billion in extra revenue for Microsoft per year, but would remove an incentive to buying Windows-based tablets.

A Microsoft Office logo is shown on display at a Microsoft retail store in San Diego in this file photo from January 18, 2012.  REUTERS/Mike Blake/Files
A Microsoft Office logo is shown on display at a Microsoft retail store in San Diego in this file photo from January 18, 2012. REUTERS/Mike Blake/Files (MIKE BLAKE)

"We don't take it from the point of view, 'Do we need to have the PC software that's running on every single device?', we look very much at 'What is the experience that we are looking to have on those devices'," said Kurt DelBene, head of Microsoft's Office unit, asked about Office on the iPad at the Morgan Stanley technology investor conference in San Francisco, which was Webcast.

DelBene, who took over leadership of Office from Stephen Elop who left to lead phone maker Nokia in 2010, did not directly address putting native versions of Office applications on the iPad, a subject Microsoft has steered clear of in public.

Asked specifically about the availability of Office on Apple's iOS mobile system - which powers iPads and iPhones - DelBene instead stressed online versions of Office apps, which can be accessed via a browser but do not offer the full richness of installed software or an app.

"We've actually done a lot of work on iOS devices this time around," said DelBene. "We have enhanced the web applications pretty substantially, in partnership with Apple."

Microsoft does offer native iOS versions of some Office applications, including its OneNote note-sharing software, Lync communication suite and SharePoint collaboration site, as well as its SkyDrive online storage service.

But the more than 100 million iPad owners, many of whom want to bring their devices to work, have to use the limited online versions of desktop staples Word, Excel and PowerPoint.

Morgan Stanley analyst Adam Holt estimated earlier this month that Microsoft could generate $2.5 billion in extra annual revenue from Office on iPad by next year, less the commission Apple would take on sales of Office through its App Store.

But the risk for Microsoft is that putting Office on the iPad takes away one of the key advantages of its own Surface and other Windows tablets, that already run Office natively.

Removing incentives to buy Windows tablets would be a blow to Microsoft's flagship Windows unit, which although less profitable than Office, is still key to the company's overall strategy.

Asked by one investor at the conference when he would be able to use Excel on his iPad, DelBene instead pointed the questioner toward Microsoft's own Surface RT and Surface Pro tablets and urged him to use Web-based versions of Office apps.

"I think we've done a great job on both the consumer side, particularly with the Web apps that we are building, and on the enterprise side as well," said DelBene.