St James's dealer Max Rutherston made his fears known ahead of the General Election, commenting on the Conservative manifesto pledge to end the ivory trade.
The other major parties are yet to declare their position on the issue.
Mr Rutherston - until last year chairman of the ten-day Asian Art in London festival - specialises in netsuke, many of them carved from ivory. Around half his sales involve ivory.
"The American moratorium has already made my business difficult in recent months," he said. "A UK total ban on ivory sales would almost certainly make it unviable."
Mr Rutherston is calling for politicians and campaigners to "focus on the true criminals here, who are the poachers and those who trade in the fruits of their cruelty".
His comments came as it emerged that the Conservative Party had included a similar pledge to end the ivory trade in their 2010 manifesto. However, then they also promised to destroy existing stockpiles, making it appear that they were really concerned with contraband.
The stockpile clause is missing from the 2015 manifesto and Conservative Central Office's confirmation toATGthat they really did mean a total ban, including antiques, sparked uproar when reported last week.
One of the most vocal critics when the news broke on Twitter a week ago was silver dealer Michael Baggott who said: "It's alarming because of what's happened in America. People in the trade have said to me: 'A ban on ivory means the destruction of items which only have ivory as an element in them'. Somebody will work out that there will be a way of removing the ivory to make money. Hundreds of thousands of objects would be ruined to make a few pounds."
Mr Baggott believes that much of the problem has arisen as a result of the growing wealth in China.
"Ivory has such a cultural significance in China these days and now they have the money to pay for it. The law won't stop the poachers if rich Chinese are still prepared to pay for it," he said. "The bizarre thing is that modern ivory is already banned. What it needs is on-the-ground policing to stop the corruption."
He also believes that people are backing a campaign that they don't understand. "There's a fundamental lack of understanding of what antique ivory is. If you showed a member of the public 500 portrait miniatures and said do you want these destroyed, they would be aghast."
It's a point not lost on portrait miniature specialist Emma Rutherford, who also went on Twitter to spread the word.
Rebecca Davies, chief executive of LAPADA, expressed her association's "deep concern" at the manifesto policy.
She said: "Few people realise the breadth of antique items that are crafted from or contain ivory. Enacting a blanket ban will not save the elephants and so much more would be threatened instead.
"Many dealers have already seen a major impact on sales to the US market and this type of legislation would be the final nail in the coffin for many of them whose expertise is focused on items that historically contain ivory."
Mr Rutherston agreed: "The current turmoil in the United States appears to stem from an intellectually feeble reaction to a real problem.
"Responsible supporters of the continuing trade in antique ivory are quick to emphasise that they condemn the poaching of elephants, and I doubt that they would object to an outright universal ban on the trade in unworked or newly worked ivory."
He said that CITES has proved an acceptable and effective way of controlling the legitimate trade and backed V&A curator Dr Marjorie Trusted's view, reported in last week'sATG, that it was not difficult to distinguish between antique and modern works made from ivory.
"If there is room for doubt about whether an object was made before 1947, so be it; decline a licence to the dubious object. In this respect, I think that the system may in part be self-policing," Mr Rutherston added.
Borwick Seeks Clarification
ATGasked the Liberal Democrats and Labour to give their position on the ivory as neither included it in their manifesto, but neither replied before deadline. Nor did the Scottish National Party when asked to clarify its position: it mentions only enforcing the ban on the illegal trade in ivory.
Nonetheless, Kensington and Chelsea Conservative candidate Victoria Borwick, a former fairs director at Olympia and Deputy Mayor for London, was clear that she did not back her own party's manifesto pledge.
She has written to DEFRA parliamentary under secretary of state Lord de Maulay asking for clarification and for him to put dealers' minds at rest. She has told him that the trade would support the ban on modern ivory, but not antiques, and argued that Conservative policy was to back existing CITES rules.
She also toldATGthat if elected on May 7 she would continue to press the matter and stand up for the art and antiques trade regardless of which party came to power.