The Tánaiste and Minister for Foreign Affairs has said he is in no doubt that "the continued bombardment on Rafah will constitute a war crime" and "gravely violates international humanitarian law".
Micheál Martin was speaking after Israeli special forces launched an operation in the southern Gaza city in which at least 67 people were killed and two Israeli hostages freed.
"We are looking at now what is the largest refugee camp in the world in terms of 1.5 million people in Rafah," Mr Martin said.
"They cannot be displaced safely.
"To bomb and to mount a military operation in such a confined area with so many people is absolutely inhumane, unacceptable, and the international community must do everything it possibly can to put the pressure on Israel not to proceed with this invasion.
"It is very, very, serious. It will create catastrophic conditions on top of what are already dire situations for families and civilians in Gaza."
Mr Martin described what is happening in the territory as unacceptable.
"We have to do what we can, which we will through the various fora that we are members of, particularly the European Union and the United Nations, working with the Arab nations as well, making it very clear to Israel that we view this as a violation of international humanitarian law," the Tánaiste said.
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He also said that Ireland "is, and remains, strongly supportive of UNRWA [UN agency for Palestinian refugees] and will continue to be because in respect of getting vital humanitarian supplies to Gaza, to Palestinians more generally in Jordan and in the West Bank, in particular, UMRWA is absolutely essential.
"There are 30,000 in UNRWA across all the region, 13,000 in Gaza alone and in respect of education, and in respect of health services and food, and vital humanitarian supplies, there is no option, actually, but to continue with supporting UNRWA and I will be meeting with Philippe Lazzarini, the head of UNRWA this week," Mr Martin said.
'It's not a decision taken lightly'
Israel's Ambassador in Ireland, Dana Erlich said that the Israeli operation in Rafah is part of the overall operation to bring back all of the kidnapped people and eliminate Hamas.
"This is what we are doing in a very calculated systematic way, it's not a decision taken lightly or made quickly.
"We are doing it under international law to making sure to minimise civilian causalities as possible."
She said that everyone is concerned for what is going on in Gaza and Rafah, and how Hamas is embedded in civilian infrastructure, hiding behind the civilian population, and that the true tragedy of this war is the cynical playbook of Hamas.
She said that humanitarian corridors would be set up for evacuation to safe areas.
"We ask international community to help make sure that casualties are minimised, we can do it."
She said that Rafah is an active combat zone as Hamas is moving and there are 134 hostages waiting to be rescued.
She added that Israel does not know how many people have been killed and cannot put an official number on it. She said that the numbers and information given by Hamas need to be questioned, including the amount of people reported dead by authorities in Gaza.
Asked about the death of six-year-old Palestinian girl Hind Rajab, who had begged Gaza rescuers to send help after being trapped by Israeli military fire, Ambassador Erlich said she did not know what exactly happened in this case.
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"We've seen how Hamas take over ambulances, we’ve seen how they embed themselves in the hospital.. According international law, when on that ambulance there are terrorists, or are on the way to perform an attack.. We don’t have all the information."
She said that Israeli authorities value human life, both their own and neighbours, and ask the international community to work with them to make sure those lives are safe.
