The Irish president has been accused of spreading "inflammatory" misinformation about the Hamas terrorist attack.
Michael D Higgins condemned the blast on the Al-Ahli Arab Hospital in Gaza last week and said it must be investigated as a war crime.
Speaking in Rome last week, the Irish president said he was "shocked" and "horrified" at the latest escalation of the conflict between Israel and Hamas.
Higgins said: “Once the facts are available to you, the moral responsibility is on you, both from any kind of jurisprudence and any type of law, to bring it and to deal with it appropriately."
Higgins also accused the Jewish state of breaking international law and claimed Israel deprived over two million people in Gaza of basic human rights such as food, water and medicines as illegal.
He added: "Of course it's a breach of international law. If there is not international law to protect civilians, what world are we to live in?
"What's at stake here is, if you have been at the receiving end, as indeed Israel has, of a horrific attack, does it confer an impunity on you in relation to law? Of course it does not."
The comments sparked a row on the Irish president constitutional role and whether he should be commenting on day-to-day political issues.
Israeli ambassador to Ireland Dana Elrich told the Irish Sunday Independent newspaper: "We know the President's position and we know he holds this topic very closely.
“For me, it is frustrating when public figures and elected officials repeat misinformation."
Ned O'Sullivan, a senior Fianna Fáil Senator, said: “The president is not a sacred cow.
“That man does not have the right to do what he did. Someone has to call him out on it. His term is nearly over. God only knows where he will stop.”
Asked about Higgins’ comments, Ireland’s Deputy PM Micheál Martin said he doesn't "comment on comments that the president makes on a variety of issues".
Speaking to reporters in Dublin, he added: "I've never attempted to do that or embroil the president in any controversy, and I don't intend to do so now.
"My focus is very much on the issues of the day in terms of the Middle East and in terms of the Israeli-Palestinian conflict and the need to de-escalate, and the need to get humanitarian supplies in there, hence our calls for a humanitarian ceasefire."
Hitting back at the criticism, Higgins said he had a responsibility to speak on behalf of the Irish people.
The IDF said the blast at the Al-Ahli Arab Hospital in Gaza was caused by a misfired rocket from the Palestinian Islamic Jihad group and released imagery and communications intercepts aimed at supporting their case.
Meanwhile, Hamas claimed an Israeli air strike led to the blast, with Gaza health officials saying it killed at least 500 people.