Mining billionaire Clive Palmer has stepped back from some of the colourful remarks he made yesterday about the Greens and conservationists, which Foreign Affairs Minister Bob Carr said could undermine Australia's investment appeal.

Clarifying yesterday's broad spray in which he claimed the Greens and the environmental group Greenpeace were tools of the CIA in a plot to undermine Australia's coal exports, Mr Palmer narrowed his accusations late last night to elements of the Greens movement in Queensland.

Colourful claims ... Clive Palmer. Credit:Glenn Hunt

"A lot of the people in Greenpeace are good people. But I don't like the idea that they are being funded by foreign people and many of them don't even know it," he told the National Times.

"I personally think [Greens leader] Bob [Brown] is pretty sincere. I don't agree with him, but the point is I think he's Australian. I don't question his loyalty to Australia. I personally don't think Bob Brown would be associated with foreign groups.