The Irish Creamery Milk Suppliers' Association (ICMSA) is calling on dairy processors to provide farmers with a milk price of "at least" 48c/L for supplies in September.
The association said that dairy markets have moved forward considerably in August and September, and called on the processors to "send a strong signal" to milk suppliers that the improvements in the market in recent weeks will be passed back "quickly" to farmer suppliers.
Noel Murphy, the ICMSA's dairy chairperson, said: "While farmers' milk prices did increase in August, the relatively small increase did not reflect the true scale of improvement, and milk processors...need to make a very strong statement for September milk.
"There is a crisis of confidence at farm level and we can't overstate how important it is for co-op boards to look at the market and ensure that farmer suppliers are getting what they are due.
"Those market-reflecting prices are desperately required if farmers are to be given a chance to start paying down the bills and loans that have been mounting up for the last year," Murphy added.
According to the ICMSA, demand and prices have moved forward considerably in a number of markets, including the EU, New Zealand and the US.
Prices for butter in the Netherlands have increased from €6,820/t on July 31 to €8,000/t on October 2, an increase of around 17%.
Meanwhile, over the same period, whole milk powder has increased from €3,860t to €4,410/t, and skim milk powder has increased from €2,330/t to €2,520/t.
Murphy said that these figures "clearly support the ICMSA position that markets have moved on considerably, and this must be acknowledged in farmers' September milk payments".
"Milk prices did move forward in August, but the price paid to farmers was demonstrably lower than it should have been. We know it and so do the co-ops," he said.
"We think that 48c/L should have been paid for August milk and we are absolutely sure that 48c/L is due for September milk. Farmers are due that, they expect that, and they should most definitely be getting it," the ICMSA dairy chair added.