Vietnam has rejected accusations made by Google and McAfee that malicious software had been used to spy on tens of thousands of Vietnamese web users.

The companies said the software had been used to target anti-government blogs and websites.

McAfee said the perpetrators of the attacks "may have some allegiance" to the country's government.

But Foreign Ministry spokeswoman Nguyen Phuong Nga said the accusations were "groundless".

"We have on many occasions clearly expounded our view on issues relating to access to, and use of, information and information technology, including the internet," she told reporters.