The Government is to consider raising the limit on the amount of corporate funds which can be donated to political parties.
The move was last night criticised by the new Labour Party leader, Mr Pat Rabbitte, who said it was extraordinary coming just weeks after the publication of the interim report of the Flood tribunal.
A spokesman for the Minister for Environment confirmed that Mr Cullen planned to rewrite the Electoral Act, which sets limits on political spending and donations.
The spokesman stressed that Mr Cullen would be looking at "all aspects" of the Bill and would not be adjusting just the cap on corporate donations.
It is understood the Minister feels there should be more emphasis on making the donations transparent rather than on limiting their size.
Under the Electoral Act, political parties can accept donations of up to €6,348 in a given year, while donations to individual politicians are limited to €2,539.
The cap has hit the finances of Fianna Fáil hard in the circumstances of a general election and two Nice referendums. A Government source said last night there were people who wanted to make donations to the Nice campaign but couldn't because of the cap.
Mr Cullen said in a weekend interview he believed there was almost a duty on business to support the political sector. However, he said, a new system would have to be transparent and all donations would have to be openly declared.
The Act was too restrictive and his overriding concern was that any new system should be "absolutely transparent". Limits would be secondary to that, he added.
Mr Rabbitte said last night that public confidence in the political system had been significantly undermined by disclosures at various tribunals and by the way certain politicians, mostly from Fianna Fáil, were in the pocket of sections of big business.
"I believe that the only way in which confidence can be restored is by a total prohibition on donations from the corporate sectors," he said.
Mr Rabbitte said he was concerned that the Government was apparently planning to substantially increase the amount that candidates and parties can spend during an election campaign.
"These were already significantly increased in advance of the last general election, but now it appears that the Minister for the Environment wants his party to be able to spend even more in their efforts to buy the electorate."
News that the Government wants to ease limits on donations comes in the same week as the Flood tribunal is due to sit again to hear more allegations of political corruption in Dublin County Council.