Licensees are facing uncertainty over the supply of Britvic products following the introduction of a new supply system.
The soft drinks company, whose brands include J2O and Britvic juices and tonics, has recently introduced a new purchasing software programme, which the company says will make the ordering system "a lot more efficient".
However, Ted Kukielka, licensee of Punch tenancy the Roaring Donkey in Swindon, said he has been having problems getting hold of products for the last six weeks: "One week I can't hold of tonics, the next it's baby orange juices and it keeps happening. I am surprised that a company the size of Britvic is running out of stock."
A spokesman for Britvic said: "We admit there have been a few technical glitches with the new system.
"When the procedure began Britvic did send out letters to all of its customers telling them this would be happening - so people should be well aware of any potential problems. Britvic is treating this problem with the utmost urgency in an effort to get it sorted out."
However, Mr Kukielka, who is tied into buying Britvic products said he has been kept in the dark about the problem for some time.
"I only received a letter about this yesterday. Britvic may say it sent out letters when this process began but I have been having problems since early March and the letter I received was dated April 2005. It's all a little baffling. I am now stocking Schweppes products."
Richard Smith, licensee of Bar One Nine in Keynsham, Bristol, said that while he had not experiencing such problems, he was concerned. "To be honest I have a lot of sympathy for people who are tied in when problems occur. This is exactly the sort of thing that forces people to buy out of the tie," he said.