The Taoiseach has said the Government will aim to draw up legislation by the weekend to plug the loophole created by last week's Supreme Court ruling.
Under the 1935, Criminal Law (Amendment) Act, it was automatically a crime for a man to have sex with a girl under the age of 15.
Last week, the Supreme Court ruled that the law was unconstitutional because it did not allow a defence of making a genuine mistake about the girl's age.
Mr Ahern told the Dáil that, if possible, the legislation will be brought before the Houses of the Oireachtas next week.
He said the Governor of Arbour Hill will appeal today's decision to the Supreme Court.
Any legislation is likely to introduce a uniform age of consent of 16 for both girls and boys.
A government spokesman earlier said the Minister for Justice, Michael McDowell, was not in a position to bring any specific proposals to this morning's cabinet on the fallout from last week's Supreme Court ruling.
The Minister presented cabinet colleagues with an aide memoire setting out the options.
The spokesman said this morning's discussion centred on the degree of protection needed for young people and the age band at which those protections might be appropriate.
He said that Mr McDowell would now be moving to drafting more detailed proposals with the likelihood of meetings over the weekend ahead of the possible recall of the Dail next week.
The spokesman insisted that the Justice Minister had only heard of the imminent judgment last Tuesday and maintained he was not aware of any earlier contact with government from the Attorney General's office on the issue.
It is understood that the Minister for Justice, Michael McDowell, will propose the new age of consent of 16 - up to now it had been 15 for boys and 17 for girls - while it will also become illegal for women to have sex with underage boys.
However, the minister is also expected to propose that a teenager can have sex with someone between the ages of 14 and 16 as long as they are not more than two years older than the younger person.
