The Minister for Transport, Mr Brennan, offered his apologies to the Cathaoirleach of the Seanad, Mr Ruairí Kiely, yesterday.
The apology arose out of a recent function attended by the Minister and the Cathaoirleach at Shannon Airport.
Mr Brennan was in the Seanad to speak about road safety.
While welcoming him to the chamber, Mr Kiely said that the opposition was anxious that he attend there often.
"Maybe if you did, you might be able to recognise the Cathaoirleach when acknowledging public representatives at functions in the mid-west.
"It was demeaning to this high office and disappointing, especially when you started off your parliamentary career in this House in 1977 when you were appointed by the then Taoiseach, the late Jack Lynch. It was also the first year I was elected to this House."
The Minister said he offered the Cathaoirleach his sincere apologies.
"I overlooked doing the correct thing when I met you last time," he said.