An Opera spokesman said on Friday that the Norwegian browser company has not been approached by Google about a possible acquisition.

"These are just rumours. We have not been approached," said Tor Odland, communications director at the firm.

The whispers appear to have stemmed from a blog posting on Tuesday by Pierre Chappaz, a former head of Yahoo's European operations. "According to a source who is usually well informed, Google is close to acquiring the Opera browser," he wrote in his blog (in French).

Officials at Google were not immediately available. A spokesman with the company's public relations agency in Europe had no comment to make.

One analyst said buying Opera would make sense for Google, particularly given its expansion beyond search and its apparent ambition to offer productivity applications over the web as a service.

Google announced a partnership with Sun Microsystems in October, part of which included finding ways to expand the distribution of, the open-source productivity suite on which Sun StarOffice is built. The companies offered few details, but some analysts saw it as a move towards Google offering hosted applications.

"Having a browser would make it easier to do the software-on-demand type of proposition they are getting into with Sun and," said Mike Davis, a senior research analyst at the Butler Group. "From a pure design point of view, you want to have control over not just the back-end systems but the whole delivery process to the end-user."

Google could also optimise its own browser for even faster web searches, Davis added. "It would be able to produce something very fast and slick and accessible," he said.

The search firm will inevitably have its own browser eventually, according to Davis – the question is only whether it will acquire one or develop it in-house.

The company has already been rumoured to be developing its own browser. "Buying an established one that already has a presence and a level of respect would be a sensible thing to do if it wants to continue its expansion outside search," Davis said.

Another analyst called the discussion a good rumor that's sure to "keep the perceived Google-Microsoft rivalry ratcheted up".

"Whilst it may be difficult for Google to make any direct income from acquiring a browser, there might be the advantage that the company could package a browser pre-configured with Google goodies that it could then attempt to get PC suppliers to preload as part of machines' base install," said Tony Lock, chief analyst at Bloor Research.

"This would give customers an alternative to Internet Explorer, but one with Google 'preferences' rather than Microsoft's."

In his blog posting, Chappaz said such a move by Google would allow it to respond to Microsoft if the company were to integrate its MSN search engine more tightly with its Internet Explorer browser.

For its upcoming IE 7.0 product, Microsoft could take inspiration from Firefox and feature its search engine more prominently, Chappaz wrote. Google appears prominently as the default search engine in Firefox.

In an 18 November blog posting, Chappaz also predicted that Yahoo would buy Yahoo announced that it had acquired the social bookmarking company on 9 December.