The Taoiseach has said he is disappointed that he only found out yesterday about a driving ban served by Minister for Agriculture Barry Cowen four years ago.
Micheál Martin said he has spoken to Mr Cowen, who has said he is "profoundly sorry" about the drink-driving incident.
The Irish Independent reported that Mr Cowen served a three-month disqualification from driving in 2016.
In a statement to RTÉ News, Mr Martin said he was first made aware of the issue yesterday afternoon.
"I have spoken to Minister Cowen and I accept that his remorse about this incident is genuine," the Taoiseach said.
"I am disappointed that I learned about it in this way and have made that clear to him."
Minister of State for Employment Affairs and Retail Businesses Damien English has said the issue of whether Mr Cowen should have informed Mr Martin about his driving ban before his appointment is an issue for the two men involved.
Speaking on RTÉ's Saturday with Cormac O'Eadhra, he said Mr Cowen has openly said that he was wrong and has accepted his punishment.
Mr English said it was a matter for the pair of them to sort out amongst themselves and that he would judge Mr Cowen on his future political actions.
Speaking on the same programme, Sinn Féin's Louise O'Reilly said the issue was one of communication.
She said: "There appears to have been a very fundamental breakdown between Mr Martin and one of his senior people."
She said to be fair to Mr Cowen he addressed the issue and accepted that he was wrong.
Co-leader of the Social Democrats Róisín Shortall said it was incredible that an experienced politician "had not got the message" on drink-driving.
She said it needed to be called what it is and that she was surprised he did not tell Mr Martin sooner.