Fluent Irish speaker Enda Kenny is to end compulsory teaching of the language if put into power.
The Fine Gael leader confirmed his party's election manifesto includes proposals to abolish the subject's mandatory status in the Leaving Certificate.
In an interview on Raidio na Gaeltachta's Adhmhaidin morning show, Mr Kenny said Irish as a compulsory class had clearly failed.
Micheal Martin, Fianna Fail leader, attacked the move, saying: "Making Irish optional is not an option as far as I am concerned. It would lead not (to) the revival of Irish by 2030 but to its extinction."
Mr Kenny denied his proposals would decimate the Irish language summer college industry, an essential part of the Gaeltacht economy across the west and north-west.
He said the party intends to consult with experts and stakeholders before lifting the mandatory status but that the plan would go ahead with the oral worth 50% of marks in the Irish Leaving Cert.
Fergus O'Dowd, Fine Gael education spokesman, said Fianna Fail has no credibility on the language as it took them 13 years to publish a strategy.
"It is long-standing Fine Gael policy that Irish should be optional after Junior Cert but we do understand some people's concerns and we do want to listen to them," Mr O'Dowd said.
"Many stakeholders have passionate and long-standing beliefs on this issue and Fine Gael will consult with these stakeholders before the introduction of Irish as an optional subject."
He added: "Fine Gael will double the proportion of Irish students sitting the Higher Level Leaving Certificate exam by 2018."