MOUNTAIN VIEW, Calif. — Google Inc. plans to start selling advertising space in 50 top newspapers, expanding the Internet search engine's efforts to provide services off the Web and making it easier for companies advertising online to also show off their products in print.

A group of more than 100 Google advertisers will be able to place bids for space in newspapers owned by The New York Times Company, Gannett, the Tribune Company, the Washington Post Company and Hearst during a three-month test period, according to news reports.

Many newspaper executives see the proposed system as a way to increase sales as they struggle with reader defection and competition from online advertising. They downplayed any risks of letting Google handle their relationships with advertisers.

"We go into this with both eyes open," Mike Lemke, senior vice president for sales and marketing at Seattle Times Co., told the Wall Street Journal.

The move also positions Google -- already the biggest seller of online advertising -- to gain more customers during its pursuit of print, radio and television advertising.

"Print adds value the Internet doesn't have," Tom Phillips, who runs Google's print operations, told The New York Times. "It is a different browse-able reading medium."

The newspaper program, to be launched this week, will enable advertisers to pick specific newspapers and specific sections for their ads. Businesses would place bids on ad size, sections and days a newspaper is offering and the publication can view the bids and make selections. The newspapers can choose to accept as many or as few bids as they like at any time.

Executives said the system allows newspapers to tap into a group of advertisers they don't currently get, including smaller businesses and retailers.

Google will not earn any revenue during the test, but when the system is formally introduced next year, it will take a cut.