Heineken UK is introducing a minimum delivery scheme from 1 August — meaning pubs will need to order three kegs or more of beer or cider per week or they will no longer be able to order through the brewer.
Under the terms of the scheme, any pub unable to place the minimum weekly order will either be asked to order every two weeks, or be passed the details of local wholesalers.
Licensee John McMennum, of the Sportsman Inn, Toft Hill, County Durham, has called the situation "horrendous".
He is concerned as he orders not just his beer and cider through the brewer but also packaged drinks such as Red Bull and J20, and cleaning products.
He said: "We are a freehouse and struggling to keep afloat. We are going to get sidelined and have to go to a wholesaler but we don't get the same level of discount with them. I don't know what our future holds."
David Jones, a spokesman for Heineken UK, said: "Heineken UK is introducing a minimum-delivery scheme from 1 August in order to address the disproportionately high financial and environmental costs associated with the delivery of small orders.
"The small percentage of our customers who are unable to place a weekly order of three kegs or more of beer and cider will be asked to consider placing orders on either a fortnightly or monthly basis.
"Alternatively, we can recommend wholesalers in the area who supply our brands and they may be able to offer more flexible deliveries.
"As a responsible brewer, Heineken UK is committed to reducing the environmental impact of its business and this change to our delivery patterns will contribute towards this aim."