The head of the Scottish Chambers of Commerce said there had been no reports of business leaders being bullied or put under pressure over independence.
Chief executive Liz Cameron said any such intimidation would be “totally and utterly unacceptable”.
The SNP’s leader at Westminster, Angus Robertson MP, has faced claims that he personally attempted to prevent some heads of business from speaking out.
A television documentary earlier this week suggested a former boss of the Scottish Whisky Association (SWA) had been warned to stay out of the debate.
However, the current SWA chief executive insisted no-one had attempted to bully him during the campaign.
Speaking on a visit to the north-east for the Aberdeen and Grampian Chamber of Commerce Meet the Leader series with Alex Salmond, Mrs Cameron said a survey of 11,000 chamber members showed the standard of debate so far needed to be raised.
She said: “We do appreciate that, at the end of the day, businesses will make a decision based on the facts that are presented, and we have got to steer through the political messages and get to the real economic answers that we need to help us make our decision.
“In terms of the issue about businesses being afraid to speak out, my response to that, as far as Scottish chambers is concerned, I have not had individuals coming forward to me with that issue.
“I would urge any business that is placed in that position that our door is open to listen, because that would be totally and utterly unacceptable.”
Speaking after the event, Mr Salmond said he needed to win the support of Scottish businesses, but stressed that each chief executive or managing director would only have a single vote in the referendum, like every other resident.
He said: “Some of Scotland’s greatest entrepreneurs like Brian Souter, Jim McColl have already declared for independence, these things are important, the business community is very important to the future.
“I should say that in the referendum, everybody has one vote. I’m delighted to be here with the chamber of commerce today, but on Tuesday I was campaigning in Northfield, which incidentally is running very heavily in favour of yes in my opinion. The beauty of this referendum is that everyone has one vote.”