The Government faces a stiff timetable to put legislation copperfastening electronic voting through the Oireachtas in time for the local and European Parliament elections on June 11th.
Despite protestations by the Taoiseach, a number of senior Fianna Fáil figures have already begun to warn privately that the €40 million system may not be used in the coming elections.
In the Dáil, Mr Ahern said: "The legislation will be prepared as a matter of priority. It is intended that it will be passed in more than sufficient time for electronic voting to operate nationwide in June."
The Bill will be complex since it will have to provide for the creation of an independent panel to verify the system's security and measures to allow voters to abstain.
Statutory instruments will have to be introduced after the primary legislation is passed, though such regulations must lie before the Dáil for 21 sitting days before they can come into effect.
Even if the Minister for the Environment, Mr Cullen, published the legislation today and it was passed immediately by the Oireachtas, it would not come into effect until early May.
Yesterday, the Department of the Environment, Heritage and Local Government could only say that the legislation would be ready "as quickly as possible".
Labour TD Mr Eamon Gilmore made clear that the Government would be opposed if it tried to use a Dáil guillotine to force the passage of the legislation.
Once again rejecting the Opposition's demand that a paper record of each vote be kept as "nonsensical", the Taoiseach said the Government was satisfied that the system would be secret and accurate.
Even if provision was made for paper records, it might not ease concerns, since electronic counting will always produce different results from manual counting because of the vagaries of proportional representation.
Under existing election law, the State uses a limited form of proportional representation where votes to be transferred in later counts are chosen randomly from different electoral areas.
The counting machines will operate by the same principles but this means that different, but still entirely correct, results will be achieved if a paper vote is held to check the electronic count.
This is because the ballots chosen randomly by the computer system would not be the same as those chosen randomly by a human operator.
Operating perfectly, the two methods of counting could only agree on the first counts and on the votes left by candidates who are eliminated, though this may satisfy Opposition demands. The two systems could only produce the same final result if "pure" proportional representation is used, where every single preference vote is counted and distributed.
The Government intends to introduce this change later on, though the former minister for the environment, Mr Noel Dempsey, decided against doing so now on the grounds that too much change should not be brought in at once.
Speaking from Malaysia where Mr Cullen is travelling on EU business, the Minister's spokesman said electoral legislation had been put through the Oireachtas quickly in the past.
"What we are doing will be very clearly outlined in the legislation," said the spokesman, who accused the Opposition of trying "to undermine the public's interest in politics".
Meanwhile, the leader of Fine Gael, Mr Enda Kenny, questioned the awarding of the €4.5m public information contract surrounding electronic voting to a firm headed by a former Fianna Fail general secretary, Mr Martin Mackin.
The company, Q4, was chosen by a Department of the Environment selection committee, which included four officials from its franchise section and the Minister's part-time public relations consultant, Ms Monica Leech.
"I want the Taoiseach to explain how a politically appointed adviser sat on the final interview board for the awarding of a tender of a €4.5 million of public money," said Mr Kenny.
The Taoiseach insisted that all proper procedures were followed: "The contracts were put out in the proper way under a transparent system which has already been explained," he said.
The Minister, who was in contact by telephone yesterday with the Attorney General, will return to Ireland on tomorrow morning.