Microsoft on Tuesday publicly defended Windows in the face of unconfirmed reports that Google was shunning the operating system due to security concerns.

Google declined to respond to an AFP inquiry, saying only: "As a rule, we don't comment on operational matters."

Microsoft, however, felt that stories published in the Financial Times and elsewhere warranted a fast, firm rebuttal.

Unnamed sources at Google were quoted in the Times as saying that new hires at the US Internet colossus have been given the option of using Apple Macintosh computers or machines running on Linux open-source software.

Sanctioning moves away from Windows operating systems was described as part of a "security effort" triggered by an attack from China-based hackers that led to Google shutting down its filtered search engine in that country.

Google is also believed to be interested in shifting to a Chrome operating system it is building as a rival to Windows.

"There's been some coverage overnight about the security of Windows and whether or not one particular company is reducing its use of Windows," Brandon LeBlanc of Microsoft said in a blog post at the technology giant's website.

"We thought this was a good opportunity to set the record straight."

LeBlanc touted Windows safeguards and noted that security concerns have also been aimed at software built by Google and Apple.

"When it comes to security, even hackers admit we're doing a better job making our products more secure than anyone else," he said.

"And it's not just the hackers; third-party influentials and industry leaders like Cisco tell us regularly that our focus and investment continues to surpass others."

Windows is the foundation of Microsoft's global software empire.