"With the best will in the world, do we want a President who will be 85 in the last year?... Forget about saying 'ageism'. It is the truth," former Presidential election candidate David Norris has said.

Despite some heckles from Seanad colleagues, Senator Norris, who described himself as a friend of President Michael D Higgins, questioned the incumbent's suitability to seek a second term in office.

He also labelled Fianna Fáil's decision to instruct its TDs, Senators and councillors not to support any other candidate except the President as "very dangerous".

The Independent Senator accused the political parties of "hugger-muggering" ahead of the last Presidential election where they wanted to select an agreed candidate as they do not like Presidential elections and "have absolute contempt for the office of the President".

He was reacting to the decision made by Fianna Fáil to throw its weight behind the incumbent and expressed concerns that "Fine Gael will follow suit".

He recalled how he was "blocked" during the 2011 election and said: "I was not allowed even to speak to Galway County Council". 

Recalling his failed presidential election bid in 2011, where he came in fourth place out of six candidates, Senator Norris said: "Until I entered the race there was going to be no race. The political parties were hugger-muggering".

"They were moving towards selecting an agreed candidate because the parties do not like having presidential races.

"They have absolute contempt for the Office of the President in political terms. They could not be bothered running anybody."

Senator Norris said that President Michael D Higgins had been a very good President but he added: "In a general election, if candidate Kelly from Fine Gael was an excellent candidate would Fianna Fáil stand back and say, 'Ah no. We wouldn't go up against Deputy Kelly. He's an excellent candidate'."

Fianna Fáil Senator Aidan Davitt said Mr Norris had a "free run the last time" but the longest serving senator replied that "everything is rigged in favour of the political parties".

"The nomination process is heavily rigged in favour of the political parties. The parties do not have to go through any process. They just decide to plonk somebody in," he said.

Later, Senator Norris said, "I ran. Michael D ran. I was a great friend and colleague of Michael D and I said to him that if I was not running myself, I would be out on a bus canvassing for him.

"That is how highly I felt about him, but it did not stop me because I wanted to run.

"We should encourage that kind of attitude in people because with the best will in the world, do we want a President who will be 85 in the last year? ... Forget about saying "ageism". It is the truth."

Cathaoirleach of the Seanad Denis O'Donovan asked Senator Norris if he was suggesting he would run for the presidency again. 

But he said: "Regrettably, since my cancer operation, I have not had the energy or the strength. I would also be too old."

Fianna Fáil senator Diarmuid Wilson said that if Senator Norris put his name forward, he would drive him around the country if he was not able to do so himself.

Senator Norris replied: "That is an offer I can hardly refuse, I will have to consider it."