The Labour Party's plans to contest the forthcoming presidential election would serve only to damage the State's highest office, the Tánaiste, Ms Harney, has claimed.
Speaking in Galway, the Progressive Democrat leader said: "On many occasions in the past, not all occasions, presidents who sought a second term received all-party support.
"I certainly think that if Mrs Mary Robinson had wanted a second term, she would have been supported," said Ms Harney, who criticised signals from the Labour Party that it will put forward former minister Mr Michael D. Higgins.
"I think President McAleese has done a terrific job, and the Progressive Democrats supported her on the last occasion, when she was first nominated."
Ms Harney said the PDs had not discussed the issue, as it was waiting to hear of Mrs McAleese's plans. "In the event of her seeking a second term, it would be my recommendation to the party to support her," she said.
However, the Labour Party accused the Progressive Democrat leader of "arrogant nonsense". A spokesman said: "She is trying to argue that it is wrong to contest an election."
The Tánaiste also defended remarks she made recently in relation to care of the elderly, and which have been described as "deeply insulting" by the Labour Party leader, Mr Pat Rabbitte.
She had told a conference hosted by her party earlier this month that more needed to be done to encourage families to look after their loved ones, and this should involve a "carrot and stick" approach. "Is it fair that people require the State to pick up the bill, and then they get the benefits when people die?" she asked.
Ms Harney said yesterday she felt very strongly about the issue and felt it required further debate. This was not about saving State money, she stressed.
"It is probably about spending an awful lot more money, but ensuring that the money is spent on a fairer basis.
"A lot of families support their elderly members when they are invalided, and we have to be as supportive of elderly in their families as we are of elderly in institutions. The population is ageing and there will be a higher percentage of people to look after."
A major factor for many families was the relatively little support they received when they cared for relatives at home, she said. "The Progressive Democrats in the 1989-92 government had introduced the carers' allowance for the first time, and this had been developed very successfully," she said.
"I think we have to go beyond this and look into the future, and ensure that we encourage people to live up to their responsibilities rather than perhaps encourage them to place elderly people in institutional care.
"It is a huge issue in terms of facilities, housing needs, medical and other requirements, and many of the organisations involved in our conference were very supportive of the fact that we want to discuss some of these", Ms Harney added.