Sony said Thursday it will launch an e-reader in Japan and set up a platform for newspapers, books, comics and magazines, challenging rival Apple a day before its iPad goes on sale in the country.

The Japanese electronics giant plans to build "one of the largest eBook distribution platforms in Japan," with telecoms operator KDDI, the Asahi Shimbun company and Toppan printing company, it added.

The joint venture is to begin on or around July 1 and start services by the end of this year, with the four companies taking a 25 percent stake, they said in a joint statement.

The move comes a day before the launch of the iPad in Japan and other countries outside the United States, where print media face a steady decline in advertising and have turned to e-readers as a chance for new revenue.

Sony, which has already started e-Book businesses in the United States, plans to sell e-readers in Japan by the end of this year to mark its return to the market after it virtually withdrew from the business there in 2007.

"People's awareness of e-Books here has been enhanced rapidly," Fujio Noguchi, senior vice president of Sony Electronics of the United States, told a joint news conference with his three partners.

"A big wave of e-Book businesses has been swelling around the world, and the tide has spread from North America to Europe and Asia," Noguchi said. "This year will be defined as the first year of eBooks. Time is ripe."

The Japanese electronic book market is now estimated to be worth 46 billion yen (about 500 million dollars), with most titles distributed via mobile telephones and conventional computers.

"The introduction of digital devices that enhance the reading experience has heightened global interest in digital publishing," the four companies involved in the new platform said in the statement.

The four will also be open to further collaborations to establish an e-book market in Japan. "The eBook distribution company plans to construct an open platform which can deliver content to consumers through a range of devices."

The iPad is expected to galvanise interest in online books, magazines and other media.

Japanese news media have until now taken a wait-and-see approach to the device, contrary to their US peers.

Newspaper circulation remains robust, falling only six percent between 1999 and 2009 to 50.3 million sales daily, the Japan Newspaper Publishers & Editors Association said, better than their US peers.

However, magazine circulation in Japan has slumped by a third over the decade.