Firefox, the free, open-source browser from Mozilla, quietly gained enough users in March to finally grab 10 per cent of the web browser market, according to a report released by web audience measurement firm Net Applications.

Firefox was used by 10.05 per cent of web surfers last month, up from 9.75 per cent in February. That compared to the 84.7 per cent of users on various versions of Microsoft's Internet Explorer (IE) in March.

Apple's Safari browser took third place with 3.19 per cent of the market.

In the past year, Firefox has gained 3.34 per cent share while introducing version 1.5 of the browser with improved features. Internet Explorer has lost 3.89 per cent as users wait for IE7, which is due out this autumn and will boast improved features and security.

"With a strong feature set, aggressive product development cycle, open-source platform, and by offering the browser for free, Firefox has the strategy in place to maintain its growth," Vincent Vizzaccaro, an analyst with Net Applications, wrote in the report. But Microsoft "has the much easier task of defending an entrenched position rather than attacking one."

Netscape was the fourth most popular web browser, with 1.05 per cent of the market, followed by Opera with 0.54 per cent and Mozilla with 0.34 per cent.