Farmers are protesting in Dublin today over €35m in payments they are owed by the Department of Agriculture.
The IFA says the four month delay in making payments under the GLAS environmental scheme is unacceptable.
It says around 9,000 farmers, who have carried out works under the scheme, are now out of pocket.
The Department says the delay's because of problems with its IT system.
IFA spokesperson Joe Brady says that excuse is wearing thin: "At this stage, farmers want to be paid.
"They have paid their planners, they have paid their contractors, they have incurred the costs, they are out of pocket, they are due their money and at this stage they want payment."