The news comes amid a high-level restructuring at Weber Shandwick, which will see its regional managing director Philippe Georgiou leave the company at the end of February.
Weber Shandwick's former general manager, Sue Vey, also resigned last November and has been replaced by Naamat Baradhy, formerly of Bates PanGulf.
Aujan, which produces and distributes a string of well-known brands, including Rani, Vimto, Barbican and Cadbury, said its PR arrangements with Weber Shandwick would be reviewed at the end of the month.
"We don't have a great working relationship," said Tolga Sezer, Aujan's head of marketing. "It comes down to the skills and competencies and the level of services not meeting our expectations."
Asked about what the main sources of discontent were, Sezer said there was a "wide spectrum" of problems, including issues of cost and "quality of input".
"The single most important feedback should be in terms of strategy in PR," Sezer added. "When you look at Weber Shandwick, we tell them what we want to do and it turns into ad hoc efforts. The inputs we receive are not satisfactory."
But in a statement to Campaign, Baradhy said: "We consider Aujan an important client in our portfolio, and we are committed to enhancing our relationship with them.
"Our investments in time, efforts and people to their communication requirements have been substantial.
"Ever since the start of our retainer relationship in February 2005, our team has generated more than US$639,000 worth of PR mileage. Moreover, Aujan has been very appreciative of two major events that our team handled, as well as the regular services provided to them.
"It is indeed surprising that Aujan commented on this relationship to Campaign instead of discussing the issues at hand with the easily accessible management team at Promoseven Weber Shandwick."
In 2005 Aujan saw its revenues soar by 27% in the first six months of the year after it launched a multi-million dollar marketing and advertising campaign. It is investing around US$30million a year in promoting Barbican, Rani, Vimto and Hani, and its licensed drinks, which includes Lipton Ice Tea.
Georgiou confirmed he was leaving Weber Shandwick to work as a consultant. Vey is also working as a consultant. Both said they would continue to work for Weber Shandwick on a consultancy basis.