Mining magnate Clive Palmer has retreated from his earlier claim that he had scrapped mining projects because of the Federal Government's proposed resource super profits tax.

Mr Palmer owns one of the largest deposits of iron ore in the world, carved out in five separate projects.

The investment for the first development was secured before the super profits tax was announced.

Mr Palmer, a Liberal National Party donor, told Lateline last month he had canned two projects in Western Australia's Pilbara region because of the tax.

He said one of those projects would employ about 3,000 people and generate about $2 billion a year in exports.

But now Mr Palmer has told tonight's Four Corners program that he was probably exaggerating.

"Probably, it should have been, '[I am] slowing them down, waiting to see what happens'," he said.

Mr Palmer says he still strongly opposes the tax.

But Federal Small Business Minister Craig Emerson says Mr Palmer has revealed that he is part of a scare campaign against the plan for a resources tax.

"Clive Palmer's admission today that he is not cancelling projects just exposes as a scare campaign his activities and those of Tony Abbott and some other elements of the mining industry - a scare campaign against tax reform in this country," Mr Emerson said.

Federal Treasurer Wayne Swan told Four Corners some of the concerns mining companies had about the tax were legitimate.

-Watch the full Four Corners report tonight on ABC1 at 8:30pm.