Milk farmers' costs have risen by 2ppl since 2003, driven by bigger bills for fuel, feed, fertiliser and labour.
An NFU/RABDF study British Milk: What Price? says the average production cost for milk is currently 20.34ppl, compared with an average milk price of 18.5ppl.
Processors are blaming rising cream volumes for downward price pressure - last week Dairy Crest cited weak cream prices as the reason behind a 0.5ppl cut in raw milk prices.
But the report adds: "Not all the surplus cream is sold to commodity markets. As much as half in the case of some companies is sold to other markets with higher values."