Entrepreneur Dick Smith says he was too "gutless" to feature in an advertising campaign supporting a carbon tax because he was afraid he would be criticised by Rupert Murdoch's newspapers.

Mr Smith said he was asked to appear in the television ads alongside Oscar winning actor Cate Blanchett, but declined.

Dick Smith at the launch of his book at Dymocks in Sydney today. Credit:Peter Rae

"I didn't appear on it because I knew that I would be a front page of lies in the Rupert Murdoch press here," he said in Sydney today.