But Ireland agreed with the EU position of seeking an inquiry into abuses by both sides in the Gaza conflict.
Ireland is a member of the United Nations Human Rights Council (UNHRC), which agreed to launch an international inquiry into alleged violations by Israel in Gaza.
But the Irish Government delegation abstained from the vote, which was approved by 29 votes in favour, one against and 17 abstentions.
Only the United States voted against holding the inquiry. The 17 abstentions included the nine EU member states which are members of the UNHRC.
The majority of the UN human rights body is pro-Palestinian.
Ireland abstained based on the EU position of wanting an inquiry to look at violations of human rights by both sides, including those committed by Hamas and other militant groups.
The EU also wanted to condemn the firing of rockets into Israeli civilian areas as well as recognising Israel's right to defend itself.
As a result the EU did not support the resolution and the nine member states abstained.
The Department of Foreign Affairs said the nine EU member states agreed a position, so Ireland abstained.
Ireland's Ambassador Patricia O'Brien said Irish people have been "appalled" by the upsurge of violence in Gaza, and especially the very high and unacceptable level of civilian casualties.
"Ireland condemns both the firing of missiles from Gaza into Israel by Hamas and other militant groups, and the killing of hundreds of civilians in military attacks by Israel on targets in Gaza which fail to respect the requirement under international law for any military action to be proportionate and discriminate. It is clear to us that neither side is paying adequate regard to the cost of their actions on innocent civilians," she said at the UN human rights council meeting. The vote was taken during an emergency debate at the United Nations Human Rights Council in Geneva.
But Sinn Fein President Gerry Adams accused the Government of "political cowardice" in abstaining in the vote to set up an international Commission of Inquiry into allegations of war crimes.