Murdoch says digital will be main revenue provider

He made the comments at the Cannes Lions International Advertising Festival, according to reports, where he spoke alongside Peter Chernin, chief operating officer of News Corp.

Murdoch told the audience: "It's not just the Wall Street Journal. It's the Dow Jones Company, whose revenues are nearly 50% digital. I can see in a very few years 75% digital."

He also vowed to make The Wall Street Journal, which News Corp acquired when it bought Dow Jones in December last year for $5bn, the leading newspaper in the world and said he would keep investing in the title no matter what the economic circumstances.

Chernin said that the WSJ's audience of "money classes" was growing worldwide.

At the same time, Chernin urged advertisers to resist the urge to stop spending during the economic downturn.

"Spending marketing money in tough times, in my opinion, is the greatest investment you can make," he said. "You have so much more impact increasing your marketing spending in tough times."