Windows users have downloaded more than a million copies of the Safari 3 browser in the first 48 hours after launching on Monday, Apple revealed. The application is currently in beta with a final release slated for October.

Apple chief executive Steve Jobs said in a keynote presentation at the firm's Worldwide Developers Conference in San Francisco on Monday that he expects the Windows version to improve Safari's overall market share. 

The browser currently runs on 4.8 per cent of the world's computers, all of which are Macs.

Microsoft's Internet Explorer leads the pack with 78.7 per cent, followed by Mozilla's Firefox with 14.5 per cent, according to data from net traffic measurement vendor Net Applications. 

Apple cited benchmark studies claiming that Safari performs faster than its competitors in loading basic HTML, executing JavaScript and overall launch time.

The launch did not go entirely to plan, however. Security researchers instantly started subjecting the application to a close inspection, and it was only hours before the first vulnerabilities were reported.  

Apple issued a first update to the browser early on Thursday morning that repaired the flaws, all of which could allow an attacker to take control of a system or steal confidential information.