Requirements for candidates to run for the presidency are "too easy" and the Taoiseach does not see "any justification" for changing them, he has told the Dáil.
"I cannot see the point in having a large number of people on an ego trip to find out how few votes they can get," Mr Ahern said, and insisted that he was "deadly serious" about this.
In fact, he stressed, if he was to change the situation, he would make it "tougher" for potential candidates "rather than going the other way".
He also said that the referendum on the new European constitution was likely to take place next year.
In a staunch defence of the current presidential election requirements, the Taoiseach said, "to be frank in my personal opinion and not that of the Government, which has not considered the matter, it is too easy for candidates to run".
He is at odds on this issue with the Tánaiste, Ms Harney, who recently indicated she would like to make it easier for candidates to run for the presidency.
During Taoiseach's questions, Fine Gael leader Mr Enda Kenny asked if the Taoiseach believed the All-Party Committee on the Constitution should examine the requirements for candidates to run for the presidency.
Currently a candidate must be nominated by 20 Oireachtas members or by four local authorities.
The Taoiseach was adamant, however, that there would be no change. "I do not believe it is unreasonable for candidates to be asked to show a fairly modest degree of support from elected representatives. I am satisfied that it is possible for a substantial number of candidates to be nominated. It has been shown in the past that candidates do not have a problem in getting support. The system exists to do that."
When Independent TD Mr Finian McGrath (Dublin, North-Central) said the requirement was "prohibitive for Independents", Mr Ahern said he did not see why someone should be able to run without showing a degree of support. "I do not see any justification for changing it. While we have not had any Government discussion, this is my view."
Mr Joe Higgins (Socialist, Dublin West) said current requirements meant candidature would be confined to those who had "gone through the hoops of the political establishment. That was quite common in the Stalinist era in Eastern Europe, but it is hardly appropriate."
Rejecting this, Mr Ahern said: "I may as well be bluntly honest: I do not agree with that at all. I cannot see the point in having a large number of people on an ego trip to find out how few votes they can get." When Mr McGrath said it was "more serious than that", Mr Ahern replied, "I am deadly serious."
Earlier he told the Dáil that two documents on the proposed EU constitution were in preparation.
