Egypt has been spearheading US-backed efforts to end the fighting that has sparked spiralling protests across the Muslim world. President Hosni Mubarak was meeting his Palestinian counterpart Mahmud Abbas on Saturday.
A Hamas delegation, including for the first time senior officials from Gaza as well as members of the Islamists' Damascus-based leadership in exile, was also due to hold talks with Egyptian intelligence chief Omar Suleiman.
Abbas pressed Hamas to accept the Egyptian plan "without hesitation," saying after talks with Mubarak that "this situation does not allow us to lose time".
"Whoever does not accept (the plan) will be responsible for the continuing aggression and for bloodshed," he said.
Mubarak's plan, unveiled on Tuesday, calls for an immediate truce for a specified period, opening Gaza's border crossings, preventing arms smuggling and a call for Palestinians to resume reconciliation talks.
On the ground in Gaza, the fighting did not show any signs of subsiding, with Israel carrying out more than 40 air strikes against the territory overnight and into Saturday, targeting arms manufacturing sites, weapons depots and smuggling tunnels, the army said.
Ground troops, who entered Gaza a week ago, were involved in exchanges of fire with Palestinian fighters across the territory, it said. Gaza medics said at least eight Palestinians were killed.
Hamas and its allies fired at least seven rockets into Israel, lightly wounding two people.
In a statement, the UN said it would resume staff movements in the enclave where most of the 1.5 million population depend on foreign aid following an attack on one of its convoys that killed a driver in an apparent Israeli strike.
Both Israel and Hamas brushed off a UN Security Council resolution calling for an immediate truce in the fighting that has killed hundreds of civilians and wreaked havoc on Gaza, already reeling from an 18-month Israeli blockade.
UN chief Ban Ki-moon expressed disappointment with Israel's defiance of a resolution -- passed by 14 of the Security Council's 15 members and backed in principle by Washington -- demanding an immediate halt to the war.
"The secretary general spoke with Israeli Prime Minister Ehud Olmert by phone this afternoon and expressed his disappointment that the violence is continuing on the ground in disregard of yesterday's Security Council resolution," Ban's spokeswoman Michele Montas said.
Olmert said that Israel would not bow to "outside influence" and would not stop its offensive in the face of persistent rocket fire from Gaza.
Hamas said it was not consulted on the ceasefire resolution and would not accept a truce that did not see the lifting of the crippling blockade which Israel imposed on the territory after the Islamists seized power in June 2007.
The civilian death toll from combat in one of the world's most densely populated territories has spiralled since Israel poured in ground troops on January 3 after a week of bombardment from air and sea.
UN human rights chief Navi Pillay said on Friday that some incidents reported during the fighting in Gaza might warrant prosecutions for war crimes.
"The vicious cycle of provocation and retribution must be brought to an end," she told the human rights council, which was holding a special session on suspected violations in the Palestinian territory.
The humanitarian impact of Operation Cast Lead was also becoming more acute with the UN warning that families were going hungry as food supplies dry up.
"We are receiving reports that some people are starting to burn their furniture to bake bread and to cook," UNRWA spokesman Christopher Gunness told AFP.
Israel launched its war against the Islamists on December 27.
Since the start of the offensive, at least 815 Palestinians have been killed, including 235 children and 93 women, and another 3,350 wounded, according to Gaza medics.
Ten Israeli soldiers and three civilians have been killed in combat or in rocket attacks over the same period.
Hamas and its allies have fired more than 600 rockets, some of them penetrating deeper than ever inside Israel.