Opera has swapped Yahoo for Google as the default search engine in the Opera mobile browsers, saying the deal is an extension of a longtime collaboration on mobile products.

Without mentioning Yahoo, the Norwegian company said in a statement that Google search would be accessible directly from the Opera Mobile and Opera Mini start pages. Such a position is a huge advantage, since users would have to manually switch out the search engine for another company, something most people wouldn't bother with.

Google has been the default search option in Opera's desktop browser for 7 years. The change on Opera's mobile browsers will be worldwide, with the exception of Russia and the former Soviet Republics.

"Google and Opera have established a valuable relationship over the years and we look forward to continued collaboration on mobile products," Jon von Tetzchner, chief executive of Opera, said in a statement released Wednesday. "With 2008 poised to be the year the mobile Web goes mainstream, Google and Opera are extending this collaboration to give our users immediate access to the quality and convenience of Google's search results."

In a response sent to the tech site TechCrunch, Yahoo spun the change as its decision. "Yahoo has elected not to continue its mobile search partnership with Opera at this time," the company said.

Yahoo pointed out that its OneSearch service would still be available to Opera users. "Consumers with Opera browsers will continue to have access to Yahoo OneSearch, and as long-standing partners, Opera and Yahoo will continue to work together," the company said.

Opera Mobile and Mini are browsers for mobile phones. The former is used in smartphones while the latter targets less-advanced phones with limited browsing capabilities. According to Opera, more than 35 million cellular phone subscribers use Mini to browse more than 1.7 billion pages a month. Opera Mobile has shipped on more than 100 million mobile phones to date.

Opera Mini is available at no charge from Opera.com. Opera Mobile is available at the same site as a free trial on select platforms. Google will appear as the default search engine on Opera Mini as of March 1. The change will affect new and current users.