MLAs were warned that the repayment of EU farm subsidies could amount to "well over 110m euros", on 14 November 2011.
The comment was made by Kieran McCarthy of the Alliance party during the debate on EU financial corrections.
The DUP's Paul Frew, who chairs the agriculture committee proposed the cross-party motion.
Mr Frew said it was prompted by the European Commission's latest announcement requiring the repayment of £4m for the incorrect payment of farm subsidy.
The motion noted the potential effect of the financial corrections on the executive's budget and called on the agriculture minister, Michelle O'Neill, to make an urgent report to the assembly.
The EC announcement, on 18 October, was the latest in a series of similar calls for repayments amounting to many millions of pounds.
Mr Frew acknowledged that the minister was unable to reply to the debate as she was involved in very important discussions with the European Commission's agriculture commissioner.
Conor Murphy of Sinn Fein explained the origin of the fines.
In 2005, he said, the system of subsidy to farmers was changed to a single payment based on the area being farmed.
EU officials later raised concerns about the maps being used by the department of agriculture (DARD) to calculate the payments
Mr Murphy wanted to know how long it took DARD to take on board the mapping problem.
Joanne Dobson of the UUP criticised DARD for "long-running inaccuracies in farm payments" and said she stood by the farmers.
Mrs Dobson said it would be a shame if monies saved on the A5 road scheme would have to be used to pay back £100m to the EU.
The SDLP's Patsy McGlone said the mapping errors came about because the farmers trusted DARD and had used maps supplied by the department in making applications.
He did not believe farmers should be penalised.
Jim Allister of the TUV, who is a former MEP, said he felt some sympathy for DARD was part of the problem had been caused by the time lag in the EU's auditing process.
Mr Allister thought the fines were grossly inappropriate.
"The minister is not a minister with a grasp of her brief at all," he concluded.
Replying to the debate, junior minister Martina Anderson defended Michelle O'Neill stating that the DARD minister would be making a statement to the assembly on the matter the following week.
Ms Anderson clarified the sums. The total "disallowance" amounted to £80.6m.
She said it had been agreed to finance this mostly from end of year underspends from other departments.
The motion was passed on an oral vote.