The Taoiseach today staunchly defended the Common Agricultural Policy (Cap) in a speech seen as strong rebuttal of British aims to reform the system.
Mr Ahern said the farm subsidy system - which accounts for 40 per cent of the EU's annual budget - had been fully re-negotiated three times since 1992 and farmers should not be asked to accept any new changes.
He said criticism of the policy has been unfair and did not take account of the broader benefits it brings to the EU.
He hit back at those who claim defenders of the Cap are protecting vested interests. "Simplistic and negative statements about the Cap, many of which are themselves driven by self-interest, are continually being made."
He said the Cap, implemented in 1957, has provided food security for member states and market stability in the face of competition from areas with much larger farm sizes.
Speaking at the Iverk Agriculture Show in Co Kilkenny, Mr Ahern said: "When the Cap was established, Europe was a deficit area for many basic food products. It was the Cap which corrected that situation. Its price support mechanisms offset the diseconomies of small-scale production on European farms and made it profitable for Europe's small farmers to produce more."
If the Cap was "eliminated or significantly reduced" these benefits would be lost, production would fall and many farmers would be bankrupted, Mr Ahern said.
"There would also be a serious outflow of labour from the land of Europe. This would add to pressure on non-agricultural labour markets and on urban housing markets."
The EU would also be strategically vulnerable if it were forced to rely on imports for basic foodstuffs, he said, noting the difficulties caused by the EU's reliance on oil imports.
IFA president John Dillon today welcomed the Taoiseach's speech describing it as a strong rebuttal of British Prime Minister Tony Blair's position on EU farm policies.
"The Taoiseach is absolutely right to hold Tony Blair to the letter of the deal on the CAP budget he signed up to with the other EU heads of Government on October 2002."
Mr Dillon wrote to Mr Blair, as incoming President of the European Council in June and also met the British Ambassador in Dublin to protest at attempts by Britain to break their commitments on CAP funding up to 2013.
A June summit to agree EU budgets collapsed after Mr Blair insisted that spending on agriculture needed to be slashed and diverted to other areas particularly polcies aimed at developing a knowledge-based economy.