Google Gears is an open source plug-in for browsers, which the firm hopes will lead to the creation of new web standards.

The firm wants many of the people attending its developers conference to use the Gears tools, which are free to use, to adapt their own applications for offline usage.

Using Gears, online data that is usually held on web servers can be stored offline on an individual's computer, and then synchronised when the user logs back on to the web.

'Fills gap'

Chris Prince, the engineer leading the Gears project, told the conference in London: "We want a seamless experience between offline and online."

"This fills a gap for us," said Jeff Huber, a vice president of engineering at Google. "The internet is great, but you can't always be plugged in to it."

Initially, Google's RSS feed reader application - for reading news and blogs - will work offline, but the company plans to add other programmes, Mr Huber said.

He said Google's e-mail, calendar, word processing and spreadsheet programmes were logical candidates for offline access.

Gears works in most of the leading web browsers, such as Firefox and Internet Explorer, and will soon work with Safari and Opera.

"With Google Gears we're tackling a key limitation of the browser in order to make it a stronger platform for deploying all types of applications and enabling a better user experience in the cloud," Google chairman Eric Schmidt said in a statement.

He added: "We believe strongly in the power of the community to stretch this new technology to the limits of what's possible and ultimately emerge with an open standard that benefits everyone."

Brendan Eich, chief technology officer at Mozilla corporation, the organisation behind the Firefox browser, said: "This announcement is a significant step forward for web applications."

Cautious note

Some commentators have seen the move as a strike at Microsoft's dominance in the area of productivity applications.

But Jupiter Research analyst Michael Gartenberg struck a more cautious note about the new technology.

Writing in his blog, he said: "Folks are missing the point.

"Yes, offline functionality is required but it isn't in itself a game changer. A word processor with less functionality than WordPad isn't going to upset anyone's business model, online or off."

Google also used the conference to announce Google Mapplets, a tool giving developers the power to customise Google maps with mini-applications.

News stories, weather, housing prices, and crime figures could be combined with maps to provide a more geographical representation of data.

Speaking at the London-based conference, Ed Parsons, Google's geospatial technologist, said the firm wanted developers to help build a "geo-web".