Funding and expenses at the Áras dominated many of the exchanges of the RTÉ Radio 1 debate on the Presidency.
In what was the first presidential campaign debate between all six candidates, much of the debate focused on funding at the Áras.
Gavin Duffy said the public "don’t know if we are getting value for money" from the Áras because of the absence of information.
"It's important the people of Ireland know they’re getting value for money from the operation of Áras an Uachtaráin," he said.
Liadh Ní Riada said there had been a "failure to deliver" at Áras an Uachtaráin on a proper level of transparency.
She said the president's salary is "exorbitant", and should be "about half" of what it is, "considering families are struggling", adding that dealing with financial issues such as these was happening "seven years too late".
Joan Freeman said if there had been annual audited accounts and Freedom of Information there would be "no need" for a conversation like this.
She added: "I really do believe that we need transparency, we need to know how the money is spent, and the presidential office should be transparent."
Peter Casey said the President needed to explain why he spent €49,000 on four flights, which included a trip to Belfast.
Mr Casey said that expenses could be published tomorrow, and said he would cut the travel costs of the presidency.
Seán Gallagher said it was "extraordinary" that the public was hearing about the President staying in "€3,000 a night" hotels.
"The issue for us as taxpayers is we're not in a position to see these figures as they’re not transparent... it's shocking we had to hear through the PAC that these accounts are not audited," he said.
Mr Higgins said "everything has been properly managed at the Áras" but he accepted that the "presentation of the information" could be improved.
He said it would be useful to have an annual report on the activities from Áras an Uachtaráin, adding: "I've already put the basic costs on the website, and they are all in the C&AG report, but the presentation of the huge range of work could be done in a more accessible way".
The debate also touched on the constitutional powers of the President, and hypothetical situations about what each candidate would do in certain scenarios were put forward by moderator Cormac Ó hEadhra.
Mr Higgins' praise of Fidel Castro upon his death was also raised, with Mr Casey saying: "I’ve been to Cuba, I’ve seen how depressed people are there".
Mr Higgins said that if he were re-drafting the statement about Fidel Castro, he would probably have drawn a wider attention to the human rights issues in those countries.