Israel defended the military necessity of its Gaza offensive on Friday at the International Court of Justice (ICJ) after South Africa asked judges to order it to halt operations in Rafah and completely withdraw from the Palestinian territory.

Israeli Justice Ministry official Gilad Noam called South Africa's case, which accuses Israel of violating the Genocide Convention, "completely divorced from facts and circumstances".

"(The case) makes a mockery of the heinous charge of genocide," Noam said. He called it "an obscene exploitation of the most sacred convention," referring to the international treaty banning genocide, agreed after the Holocaust of European Jews in World War Two.

The convention requires all countries to act to prevent genocide, and the ICJ, also known as the World Court, which hears disputes between states, has concluded that this gives South Africa a right to make the case.

In past rulings, the court has rejected Israel's demands to dismiss the case and ordered Israel to prevent acts of genocide against the Palestinians, while stopping short of ordering it to halt the assault.

Ahead of Israel's presentation, several dozen pro-Israeli protesters gathered outside, displaying photographs of hostages taken by Hamas fighters on October 7 and demanding their release.

The South African legal team, which set out its case for fresh emergency measures the previous day, framed the Israeli military operation as part of a genocidal plan aimed at bringing about the destruction of the Palestinian people.

South Africa's ambassador to the Netherlands, Vusimuzi Madonsela, requested the court to order Israel to "immediately, totally and unconditionally, withdraw the Israeli army from the entirety of the Gaza Strip".

Israel's Noam said that Israel's military operations were not aimed at civilians, but at Hamas terrorists using Rafah as a stronghold, who have tunnel systems which could be used to smuggle hostages and militants out of Gaza.

Examples of alleged violations by Israel raised by South Africa were "not evidence a policy of illegal behaviour, let alone a policy of genocide", he said. Ordering Israel to withdraw its troops would sentence remaining hostages in Gaza to death, Noam said.

More than 35 300 Palestinians have been killed in Israel’s seven-month-old assault on the Gaza Strip, health officials in the enclave said on Thursday. The war began when Hamas militants attacked Israel on October 7, killing 1 200 people and abducting 253 others.

This week's hearings focus only on issuing emergency measures and it will likely take years before the court can rule on the underlying genocide charge. A decision on the request for emergency measures is expected next week.