Pascal Dangin was quoted in an article in the May 12 issue of the New Yorker, posted online, saying that he retouched the photo of women in their underwear used in one of the campaign's earliest executions.
In the New Yorker article, Lauren Collins wrote: "It turned out that it was a Dangin job. 'Do you know how much retouching was on that?' he asked. 'But it was great to do, a challenge, to keep everyone's skin and faces showing the mileage but not looking unattractive'."
Dangin, founder and head of Box Studios in New York, retouches fashion photographs and regularly works for the likes of Vogue, Dior and Balenciaga.
If the allegations are proved to be true it could be very damaging to Dove's four-year campaign and to its ad agency Ogilvy & Mather.
It would be particularly hypocritical following Dove's popular viral video 'Dove Evolution', which shows an attractive but bare-faced woman transformed with make-up, styling and retouching into a stunning model. It ends with the line "no wonder our perception of beauty is distorted".
The viral won both a Cyber and Film Grand Prix for Unilever at the International Advertising Festival last year and has been viewed more than 15m times online.
Unilever and Ogilvy & Mather were both unavailable for comment at the time of publishing. However, an Ogilvy spokeswoman told US trade journal Advertising Age that the agency disagreed with Dangin's claim.
She said: "We are unsure right now what he did. He works with Annie Leibovitz, the photographer. And we don't have any record of him actually working on any of the Dove campaign.
"There was no retouching of the women. If there was a hair that was up in the air, that might have been the kind of retouching that was done. But until I know what he actually worked on, I can't comment on it."