Taoiseach Simon Harris has said that Israel's actions in Rafah are "utterly reprehensible".
Speaking in Co Wicklow, Mr Harris said the continued bombing of Gaza was a clear violation of the ruling by the International Court of Justice yesterday.
He said Israeli Prime Minister Benjamin Netanyahu needed to desist and desist immediately from the offensive.
"The fact that Netanyahu persists in ignoring it is a cause of grave concern," he said.
"We here in Ireland took a decision this week along with Norway and Spain to recognise the state of Palestine and we did so to keep the hope and the destination of the two-state solution alive whilst others are seeking to really bomb that into oblivion.
"This situation absolutely needs to stop."
Mr Harris also condemned the treatment of Ireland's Ambassador Sonya McGuinness who was summoned to the Israeli foreign affairs ministry and reprimanded over the decision to recognise the state of Palestine.
"The way that our ambassador in Israel was treated this week is utterly unacceptable. It is not normal diplomatic practice to parade ambassadors in front of cameras and video them whilst watching a film.
"And that's not how Ireland treats ambassadors based here and we never would. We don't expect our ambassadors across the world to be treated like that.
"It's just unacceptable. we've conveyed this in the strongest possible and appropriate terms to the Israeli government."
Earlier the Taoiseach called on Mr Netanyahu to "listen to the world" and stop.
In a column for The Journal news website, he said that a "full-scale military operation in Rafah will be a catastrophe".
He also said that the decision to recognise the state of Palestine, which was formally announced earlier this week, was taken "before it is too late".
"Ireland is moving before the chance of a two-state solution is bombed to oblivion," he said.
It comes as Tánaiste and Minister for Foreign Affairs Micheal Martin has said he will be discussing steps to try to bring peace to the Middle East with EU and Arab leaders in the coming days.
He said it was time to take concrete and irreversible steps to implement a two-state solution.
Mr Martin also said all parties must, with the utmost urgency, intensify efforts to secure an immediate ceasefire, the unconditional release of hostages and urgent distribution of humanitarian aid to the people of Gaza.
Meanwhile, the former director general of the Israeli Foreign Ministry and former Israeli Ambassador to South Africa has said Israel is "very limited in what it can do" following a decision by Ireland, Spain and Norway to recognise the State of Palestine.
Speaking on RTÉ's Saturday with Colm Ó Mongáin, Dr Alon Liel said that if other countries follow suit then Israel "will be able to do almost nothing".
"If it stays only with the three countries then we will probably keep our ambassador here and call your ambassadors frequently to the ministry in Jerusalem," he said.
"Israel, I think, is very limited in what it can do but if more recognitions are in the pipeline, the less we'll be able to do with our response."
Mr Liel said the world is "slowly" recognising a Palestinian state but that everyone will know the Israeli government is objecting to it.
He said Ireland, Spain and Norway should lobby other countries to join their decision and that once there is a majority in the EU, it should become an EU decision to recognise Palestine.
"This would be an unbelievable blow to this [Israeli] government," he said, adding that more European countries should impose sanctions on settlers.
Speaking on the same programme, Sinn Féin's Spokesperson on Foreign Affairs and Defence Matt Carthy said he hopes the move "gives the people of Palestine a message that they're being heard".
He said Israel had not faced a single consequence in real terms for what it has carried out.
"We now cannot simply just continue to have the most preferrential, economic, diplomatic trading relationships with a state that is actually preventing the peace process that we know is required," he said.
"That is denying the rights of the people of Palestine and, as we speak, is engaged in what are very clearly breaches of international law."
