Opera browser goes free to fight Firefox

"We want to become the second-biggest browser. The number one is a little inaccessible," Opera Software chief executive Jon von Tetzchner told AFP in a reference to Microsoft's Internet Explorer.

A lighter version of Opera has until now been available for free download on the internet, but with ad banners.

"We've always stood up well in comparison with our competitors in technical tests but users disliked that they had to pay 39 dollars and that we had ads. We decided to eliminate these obstacles in order to attract users," von Tetzchner said.

"This decision is not aimed at Firefox. It's aimed at increasing our market share," he added.

He said Opera had between 10 and 15 million active users in the world, or "between one and two percent of internet users". By comparison, Firefox has just over five percent, he said.

"Our aim is to rise to their level and surpass them," he said.

A study published in July by the company NetApplications, which specializes in internet user statistics, said Firefox had an 8.71-percent share of the world market in June.

Opera's web browser enables users to surf the internet with voice commands and reduce the risks of identity fraud and other internet and email fraud.