Some farmers are now becoming increasingly frustrated because of delays in receiving their GLAS payments.
IFA Rural Development Chairman Joe Brady is calling on the Minister for Agriculture to instruct his department to make contact with all 3,500 farmers who are still due their 2016 payment.
So far, about 34,000 farmers have received their 85% payment for 2016.
Joe Brady says some farmers are so frustrated that they have withdrawn from the scheme.
He also says a lack of flexibility in the scheme, with amendments not being accepted, is leading to farmers not being able to comply with requirements in some cases.
Mr Brady is calling for the remaining 15% of payments, as well as another payment known as GLASplus of up to €2,000 to be made without delay
The IFA estiamtes that up to €35m is still owed under the 2016 scheme.
Meanwhile, Fianna Fail TD for Donegal and his party’s spokesman on agriculture, Charlie McConalogue, says more than 200 farmers in County Donegal are still waiting for payments.
He adds that some of these farmers are now in serious trouble as many had plans and took out loans to carry out works based on the belief they would be receiving their GLAS poayments by the end of 2016.
He says more than four months later, they are still waiting.