Liberal Democrat treasury spokesman Vince Cable says he finds the behaviour of business chiefs who backed the Tories' promised national insurance cut "nauseating".
Mr Cable has accused the 130 business leaders who publicly came out in favour of the Conservative plan of allowing themselves to be "used" by the Tories.
He said that they now needed to explain properly how they would pay for cuts in the Government's planned national insurance increase - due to come into effect next April.
"I just find utterly nauseating all these chairman and chief executives of Ftse companies being paid 100 times the pay of their average employees lecturing us on how we should run the country. I find it barefaced cheek."
Business leaders previously reacted angrily to suggestions by Gordon Brown and Business Secretary Lord Mandelson that they were "deceived" by the Conservatives.
Sir Stuart Rose, the Marks & Spencer executive chairman and one of the most prominent backers of the Tory plan, accused the Labour leadership of insulting the intelligence of the business community.
