An Israeli soldier operates in Gaza on Monday. Reuters

Israel and South Africa face off at the UN's top court from Thursday, after Pretoria accused Israel of "genocidal acts" in Gaza, charges the Israelis have dismissed as "blood libel".

In an 84-page submission to the International Court of Justice (ICJ), South Africa urged judges to order Israel to "immediately suspend its military operations" in Gaza.

South Africa alleges that Israel "has engaged in, is engaging in, and risks further engaging in genocidal acts against the Palestinian people in Gaza".

Israel's military campaign has killed at least 22,722, according to the Hamas-run Gaza health ministry. The United Nations estimates 1.9 million Gazans are displaced, with fears growing of famine and disease.

The ICJ rules on disputes between states and while its decisions are legally binding, it has limited power to enforce them.

The court could in theory order Israel to stop its invasion but it is highly doubtful it would be obeyed.

Protesters calling for a cease-fire in the Israel-Hamas war wave Palestinian flags in downtown Seattle. AP

In March 2022, the ICJ ordered Russia to "immediately suspend" its invasion of Ukraine -- a directive Moscow has ignored.

Johann Soufi, a lawyer and international justice expert, told AFP there would be an "extremely significant symbolic impact" if the court ruled against Israel.

"Of course there is the problem of implementing the decision. But at the end of the day, international justice is all there is left," said Soufi, who worked for the UN agency for Palestinian refugees in Gaza.

Israel has angrily hit back at the accusations, with government spokesman Eylon Levy vowing to fight the South African case he described as "absurd blood libel".

"How tragic that the rainbow nation that prides itself on fighting racism will be fighting pro bono for anti-Jewish racists," added Levy.

"No, South Africa, it is not we who have come to perpetrate genocide, it is Hamas," said Israel's Prime Minister Benjamin Netanyahu.

Top officials from the two countries will face off in the ICJ's Great Hall of Justice housed in the extravagant Peace Palace in The Hague — a world away from the death and destruction seen recently in Gaza and Israel.

Agence France-Presse