One of Scotland's top businessmen has accused industry body CBI Scotland of misrepresenting members.
The body's chairman, Iain MacMillan, said more tax powers for the Scottish Parliament could make it more unattractive to do business.
But Jim McColl, of engineering firm Clyde Blowers, said Mr MacMillan was out of touch with his membership.
Mr MacMillan insisted there was no doubt over CBI Scotland's legitimacy in representing its members.
The disagreement came at the launch of a campaign to give Holyrood greater control of its finances.
Some business leaders want ministers to go further than the recommendation set out in the Calman Commission on devolution, under which a Scottish income tax would be set at 10p, with a corresponding cut in the block grant from the Treasury.
Critics say this has now been overtaken by the UK government's plan to raise the income tax threshold to £10,000.
Under Calman, Holyrood would also gain new powers on air passenger duty, stamp duty, land tax and landfill tax.
Mr McMillan has argued supporters of full fiscal responsibility must make "a much stronger" case, saying the move would fragment the UK's unitary tax system and see a rise in businesses' compliance costs as a result.
But Mr McColl said: "The CBI in Scotland I think have got significantly less than 10% of the business leaders in Scotland. Iain won't have polled his members - I know many of them and I know their views are supportive of what I'm saying.
"This is a statement by an individual who administers a business organisation in Scotland. It's not representative of business in Scotland in general."
Responding, Mr MacMillan said: "CBI Scotland's legitimacy in representing its members has never been in doubt, and CBI Scotland spokesman represent the policies of the CBI as approved by its policy-making council.
"Jim McColl's attack on CBI Scotland appears to be an attempt to detract from the legitimate questions that have been put to him about providing detail to underpin his views that fiscal autonomy would be good for Scotland."
The campaign for fiscal responsibility was launched in Edinburgh by Mr McColl and Ben Thomson, chairman of the think-tank Reform Scotland.