Microsoft has initiated a fresh campaign in the "browser" wars, rolling out a new version of its Internet Explorer, aimed at taking away more market share from rival Netscape Communications Corp. Test versions of Internet Explorer 4.0, the first major update in more than a year, have circulated widely on the Internet since April, but the product was formally presented by Microsoft chairman Mr Bill Gates at a San Francisco media event and will be unveiled to Irish consumers later this week.

Microsoft gives away its browser free over the Internet, while Netscape's finances depend on more lucrative server software, but the browsers are considered a strategically critical battleground for both companies in their efforts to win over computer users and software developers.

While precise figures are difficult to obtain, most analysts agree Microsoft's share of the browser market has risen from less than 5 per cent to more than 30 per cent since the software giant declared war on its Internet rivals in December 1995. Netscape's Navigator dominates the market with more than a 60 per cent share.

Analysts say Microsoft executives are driven to win the browser war by concern that the browser is emerging as an alternative platform to the Windows operating system that forms the basis for Microsoft's industry dominance.

According to one analyst. "They (Microsoft) now want to own the desktop." Content is king in the latest generation of browser software, as Microsoft and Netscape each have enlisted scores of technology, entertainment and media companies to offer news and information directly through the browser interface.

Microsoft alone already has announced more than 250 content providers who will offer information that can be "pushed" or "pulled" automatically to the desktop, eliminating some of the need for time-consuming Web surfing.

The latest version of Internet Explorer also has an optional "desktop update" that integrates the browser with the Windows 95 interface, allowing users to browse for information on any drive as well as on the Internet or a corporate intranet.

Netscape is promising a similar add-on to its Communicator suite code-named "Aurora", which was previewed at an industry conference this week .

Microsoft promises the new browser will be faster, more secure and easier to use, with "channels" of content guiding users to major Web sites.