Efforts to secure a renewal of the nitrates derogation from 2021 could see many more dairy farmers forced to apply for the measure.
Discussions have taken place in recent weeks over the future of the derogation, with industry sources suggesting that Ireland is in for a tough fight to convince Brussels that the measure should be retained.
This comes just weeks after the Green Party pulled back from its demand in Government formation talks for the derogation to be removed.
One industry source told the Farming Independent that having staved off the threat to the derogation from the Green Party, the sector now faces an uphill challenge to get it renewed at EU level.
"We are hearing from the Commission that a renewal is not guaranteed, full stop, unless there is a good plan of action in place," he said.
"The Commission is focused particularly on water quality and will only give a derogation if improvements occur."
A significant tightening of the requirements farmers under the derogation is likely, while it is also expected that many more dairy farmers will be forced to apply for the measure.
It is understood that there will be additional requirements, including a recalculation of the N load of a cow possibly from 85kg to 89kg, and also in terms of slurry storage, spreading, and the need to prove exports where farmers operate above 170kg without the derogation.
Denis Drennan of the ICMSA said it is important to recognise that progress has been and is being made by farmers in relation to water quality - with the ASSAP programme being a clear example of farmers' willingness to play their part.
Drennan said any changes to the derogation will have to be practical and sensible and take account of the economic sustainability of farmers.
"While water quality is a concern we will not accept a situation where all the blame is placed on farmers with over-the-top requirements for derogation farmers," he said.
"Additional measures have been taken over the last year and an appropriate time should be given to determine their effectiveness .
"Also, the new REPS scheme needs to play a role in the context of farming under a derogation."