NEWS Corp chief Rupert Murdoch said Apple would sell more than 40 million iPads by 2012 as he flagged plans to put content on more tablet devices.

Appearing by video at a new media breakfast and panel debate hosted by Media in Sydney this morning, Mr Murdoch said tablet or slate computers were "a perfect platform for our content''.

"We can deliver our content to our readers when, where and how they want it. It's cheap, convenient and constantly up-to-date,'' Mr Murdoch said.

He said News already had "tens of thousands of readers'' who had downloaded apps for The Wall Street Journal, The Times of London and The Australian on the iPad, and said subscriber levels for The Times following its recent move to erect a pay wall around its online content were "strong''.

"Initial expectations that (Apple) would sell a few million (iPads) will fall way short of the mark,'' Mr Murdoch said.

"It looks like they will sell around 15 million iPads this calendar year and more than 40 million by 2012.

"And the iPad is just one of many tablet or slate computers in the pipeline. News Corp fully intends to be across all those platforms too.

"As you know, we are rolling out a paid content strategy across our newspaper websites. Already The Wall Street Journal is the largest of its kind in the world with 1.1 million paying subscribers online.

"The Times of London and The Sunday Times last month started charging for access to their websites.

"It's going to be a success. Subscriber levels are strong. We are witnessing the start of a new business model for the internet.

"The argument that information wants to be free is only said by those who want it for free,'' Mr Murdoch said.

Other speakers at the event included Member for Wentworth Malcolm Turnbull, Richard Freudenstein and Nick Leeder, who are CEO and deputy CEO of The Australian, which is owned by News, as well as Commonwealth Bank GM of digital channel marketing Andrew Murrell and UBS media analyst Richard Eary. Media editor Geoff Elliott moderated the discussion.

Mr Freudenstein said News was investing in both printed newspapers and online content, including apps, and wanted to be the pre-eminent source of news across all platforms.

Mr Turnbull, who tweeted throughout the event and recently launched his own iPhone and iPad app, cast doubt on whether consumers would pay for easier-to-navigate news content on an iPad app if they could get free news online from a multitude of other sources, citing the failed "walled garden'' experiments of companies such as AOL in the earlier days of the internet.

"The real challenge is going to be why should I pay for a newspaper iPad app when so much content is available for free,'' Mr Turnbull said.

Mr Leeder said about 8500 subscribers paid $4.99 each in the first month to subscribe to The Australian's iPad app, and although subscriber numbers had declined the following month, churn was reducing as new subscribers bought iPads and signed up.

He said using an app was a much better experience than browsing a website.

"People are spending twice as long on the iPad app as they are when they're using the website,'' Mr Leeder said.