Tánaiste Simon Harris has said it is "outrageous" that the Palestinian Authority is not allowed to attend the UN General Assembly and called it an "extraordinarily dangerous precedent".
Speaking in New York, Mr Harris said he will work with his EU counterparts at the assembly to see if there is a majority in the EU to take "practical action" to try to bring about a ceasefire in Gaza.
"The President of the European Commission outlined proposals the commission wishes to table in terms of practical sanctions and measures, which could be taken to try and change the calculus Netanyahu must be operating under, to try bring about a ceasefire, surge in humanitarian aid, an end to the genocide and the release of all the hostages," Mr Harris said.
The week's events at the UN are expected to be dominated by discussion of the ongoing wars in Ukraine and Gaza.
A conference on the two-state solution for Israel and Palestine will take place later, where more UN member states are due to recognise the State of Palestine.
Israel and the United States will boycott the summit, Israel's UN Ambassador Danny Danon said, describing the event as a "circus".
"We don't think it's helpful. We think it's actually rewarding terrorism," he said.
Yesterday, Britain, Australia, Canada and Portugal recognised a Palestinian state in a seismic shift in decades of Western foreign policy.
At the conference, several European countries including France, Belgium, Malta and Luxembourg are set to recognise the state of Palestine.
The United States and Israel firmly oppose the move, calling Palestinian recognition a reward for terror.
President of the Palestinian Authority Mahmoud Abbas will address the conference via a pre-recorded video.
Israel has said it has no confidence in the 89-year-old Palestinian president keeping pledges to reform and modernise as outlined in a letter to French President Emmanuel Macron earlier this year.
Saudi Crown Prince Mohammed bin Salman is not attending despite co-hosting the event.
"The world is saying out loud a Palestinian state and we need to materialise it. Now they need to show what these measures are," Palestinian Foreign Minister Varsen Aghabekian Shahin said.
Israel is considering annexing part of the occupied West Bank as a possible response as well as specific bilateral measures against Paris, Israeli officials have said.
The US administration has also warned of possible consequences for those who take measures against Israel, including against France, whose President Emmanuel Macron is hosting the New York summit.
The summit, ahead of the general assembly, follows Israel's launch of a long-threatened ground assault on Gaza City and amid few prospects for a ceasefire two years after Palestinian Islamist militants Hamas attacked Israel, triggering the war in the Palestinian enclave.
In Gaza yesterday, Palestinians were fleeing Israeli attacks on Gaza City. There is a growing sense of urgency to act now before the idea of a two-state solution vanishes forever.
The week's events are expected to be dominated by discussion of the ongoing wars in Ukraine and Gaza.
