Farmers are threatening to withhold milk supplies and stage protests after dairies announced a cut of up to 2p for the price they would pay for a litre.
Three dairies have recently said they are slashing the so-called farm gate price for milk.
President of the National Farmers' Union Peter Kendall said the latest cut came after one at the start of June which also reduced the amount farmers were getting for a litre by for 2p.
He told Sky News: "The real problem for us is that when we see supermarkets, and Tesco and Sainsbury's are two examples that have a price tracking formula, they're paying farmers approximately 30p. These farmers from August 1 could be on as little as 24p."
He added: "We will draw attention to that date of August 1 and say you must rescind those price cuts.
"Farmers will probably stand outside shops and say these guys are not looking after farmers."
The United Kingdom is the third-largest milk producer in the European Union after Germany and France, producing about 13.5bn litres of milk annually.
However, price wars among supermarkets, low bulk cream prices and higher input costs have hit British farmers, who are paid much less than their European counterparts.
The average farm gate price - which is the price paid to the farmer - was 27.91p per litre in April, according to the Department for Environment, Food and Rural Affairs .
That is roughly 4% less than what the farmers were being paid at the beginning of this year and 3% lower than the average price in the EU.
Mr Kendall said that the industry needed to do more to look after the interests of those at the bottom of the chain.
"Dairy Crest gave the farmers four days' notice they were going to cut the price but because of the contacts we currently have operating the farmer couldn't leave or sever that term for another year. That is a complete imbalance," he said.
"Our market has been failing to work for the dairy farmers for far too long."