Legislation which increases election spending limits from £1 million to £3 million at the next general election was passed in the Dβil yesterday.
Labour's Environment spokesman, Mr Eamon Gilmore, described the Bill in its totality as "bad legislation.
It was technically flawed and some aspects of it might be unconstitutional.
"It is giving an unfair electoral advantage to the largest political party in the State by way of the amount of money which can be spent at a general election."
He said it was introduced mainly to assist the main Government party in getting re-elected. "As such it is profoundly undemocratic."
The Bill will allow Fianna Fail to spend up to £1 million at the general election.
The Electoral Amendment Bill caused a furore before the Dβil summer recess when the Government abandoned an attempt to prohibit the publication of opinion polls in the week before an election.
In July the Seanad rejected the provision for the polls ban on the basis that the legislation was flawed and could mean that an opinion poll could be published on the day of an election.
During a 40-minute debate yesterday the Dβil accepted the deletion of the amendment banning opinion polls, without a vote.
Ms Olivia Mitchell (FG, Dublin South) said the legislation set out, not to allow for electronic voting or to make minor changes in the electoral system, but to increase - "in the case of Fianna Fail by 50 per cent - the level of spending available to political parties and to legislation for corporate donations".
She believed there should be a debate about the banning of opinion polls.
It required "striking a balance between our entitlement to information and our right to cast our vote without undue influence being brought to bear.
In the last few days before an election an opinion poll was more formative than informative.
Mr Eamon Gilmore said the Government was "most anxious" to pass the legislation because of the increased spending and it retained, in a reduced form, corporate donations which the Labour Party sought to have completely banned.
He believed the "only legislation in its entire programme the Government wants enacted before the next election is not legislation dealing with taxation or social welfare or any other matters that concern the public, but legislation that will make it easier for itself to get re-elected".
