Arab states say the 14 October debate must tackle a report which criticised Israel, after the US argued against a emergency session dedicated to it.
The UN Human Rights Council delayed its debate on the findings of the Goldstone report following a Palestinian request.
Libya's envoy to the Security Council said its aim was to "keep momentum".
Palestinian Authority President Mahmoud Abbas has come under sharp criticism at home for requesting the UNHRC delay, which followed intense pressure from the US.
State department spokesman Ian Kelly insisted the US focus was solely on reviving the stalled Israeli-Palestinian peace process and wanted "to clear the decks of any issues that might impede our progress towards this".
Palestinian officials voiced "full support" for Libya's efforts to get the issue on the agenda of the Security Council, and senior PA politician Yasser Abed Rabbo has called the request for a UNHCR delay a "mistake".
Mr Abbas himself has ordered an "investigation" into how his own government made the decision, in an apparent attempt to head off a wave of anger and protests.
'Disproportionate'
Libya is the only Arab state on the 15-member body, where US diplomats regularly use their power of veto to block measures against its close ally Israel.
The Human Rights Council will not now address the 574-page Goldstone report - which accuses both Israel and Palestinian militants of committing war crimes in the conflict - until March 2010.
The UN panel led by eminent South African judge Richard Goldstone accused Israel of using disproportionate force and deliberately harming civilians. Hamas militants were accused of indiscriminate rocket fire at Israeli civilians.
It urged the UN Security Council to refer allegations to the International Criminal Court (ICC) if either side failed to investigate and prosecute suspects.
Israel has rejected the evidence, saying it has already investigated its troops' conduct, clearing most of the subjects of wrongdoing. Hamas also denied committing war crimes.
Israeli military action destroyed thousands of homes, hundreds of factories and 80 official buildings in Gaza.
Palestinians and human rights groups say more than 1,400 people were killed in the violence between 27 December 2008 and 16 January 2009, more than half of them civilians.
Israel puts the number of deaths at 1,166 - fewer than 300 of them civilians. Three Israeli civilians and 10 Israeli soldiers were also killed.
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