The Government is expected to overhaul electoral spending laws and to increase spending limits, following the publication of the Standards in Public Offices Commission report.
The Minister for the Environment, Mr Cullen, said he wanted "a fully transparent and accountable system" that would be "clearer, more concise and more easily understood" by all.
"Problems have arisen with the complexity of existing legislation," Mr Cullen said, adding that the commission had itself pointed to the difficulties faced by those "attempting to comply conscientiously".
The Government, he said, remained committed to "full and open accountability" in electoral spending.
"I have already indicated my intention to review the present system so as to improve its transparency and simplicity," he said, adding that he hoped to have the commission's views on possible changes shortly.
Facing Dáil criticism, the Taoiseach, Mr Ahern, said the present system "is designed to make sure" that the Dáil would be "full of millionaires". "That is a bad system," he told the Labour Party leader, Mr Pat Rabbitte.
Wealthy TDs could "spend a fortune of his or her own money right up to the campaign whereas another individual who has little or no money has to fight a campaign during the three weeks," Mr Ahern went on.
Promising to oppose limits increases, the Labour Party TD, Mr Eamon Gilmore, said stronger controls and stricter limits are needed to restrain spending during and prior to an election campaign.
Mr Cullen's predecessor in the Department of the Environment, Mr Noel Dempsey, increased by 50 per cent the original limits laid down in the 1997 Electoral Act.
Yesterday's figures did not include the massive amounts spent by Fianna Fáil in the three months before the election was called, which equalled or exceeded its €3.5 million campaign budget.
"It is little wonder that Minister Cullen is already on record as wishing to scrap spending limits on politicians during election campaigns," Mr Gilmore said, given that Mr Cullen received €35,000 in political donations in 2002.