Lebanon, Morocco, and Mahmoud Abbas, the Palestinian president, have so far confirmed their participation. Tunisia has refused.
The 18-day-old Israeli offensive has exposed deep divisions among the Arab countries.
Egypt and Saudi Arabia fear a summit would produce little in the way of results and would make Arab leaders appear ineffective, diplomats said.
Amr Moussa, the Arab League secretary-general, said that Arab foreign ministers would hold talks in Kuwait on Friday to discuss "the continuation of the Israeli aggression on Gaza" ahead of their scheduled gathering.
Friday's meeting will "examine the developments relating to Israel's refusal to abide by UN Security Council Resolution 1860" calling for an immediate ceasefire in Gaza, he told reporters.
Moussa Abu Marzouk, a senior Hamas leader, said on Tuesday there was "still a chance" that his movement would accept an Egyptian ceasefire plan for Gaza.
|Abu Marzouk says there is still a chance Hamas will accept the Egyptian plan [Reuters]
"There is still a chance that we will accept the Egyptian plan," provided the "substantial reservations" of Hamas are taken into account, Abu Marzouk told Al Jazeera.
A Hamas delegation is currently in Cairo to resume talks on the Egyptian ceasefire plan.
Ayman Taha, a member of the Hamas delegation negotiating with Egypt's intelligence chief in Cairo, denied information that it would reject the Egyptian proposal in Tuesday's talks.
Salah al-Bardaweel, another Hamas delegate, said: "We are discussing the Egyptian proposal away from the media and we will deprive the enemy of any political achievement."
Mouin Rabbani, from the Institute of Palestine Studies, and contributing editor to the Washington-based Middle East report, told Al Jazeera: "Quite a bit of diplomacy is happening to quite little effect.
"We have the negotiations taking place in Cairo over a ceasefire resolution but a lot of key issues remain unresolved.
"The key issues are that Hamas, from its point of view, is being asked to raise the white flag as a condition to reach an agreement which is much more detrimental to it than the ceasefire that it agreed to last year which wasn't respected by Israel. So, at this point, there are key issues in the proposal that [Hamas] cannot accept.
"Israel is insisting on conditions that not only Hamas is unwilling to accept, but that Egypt is also unwilling to accept because it would further impinge on Egypt's already limited sovereignty in the Sinai peninsula."
Hamas says Israel must pull back all its troops under a ceasefire and end the blockade of the Gaza Strip that it tightened after the group seized the coastal enclave from forces loyal to Mahmoud Abbas, the Palestinian president, in 2007.
Israel has rebuffed as "unworkable" a UN Security Council ceasefire resolution last week and said a truce must ensure Hamas cannot re-arm through tunnels under the Gaza-Egypt border in an area known as the Philadelphi corridor.
Ban Ki-moon, the UN secretary general, was heading to the region for a week of talks with leaders in Egypt, Israel, Jordan and Syria aimed at ending the bloodshed.
"My message is simple, direct, and to the point: the fighting must stop. To both sides, I say: Just stop now," Ban told reporters before his departure.
Ehud Barak, the Israeli defence minister, said in broadcast remarks that Israel had "respectfully" heard Ban's appeal and was monitoring Egypt's ceasefire mediation, but it would continue to hit Hamas while diplomatic efforts were under way.