South Africa is asking the UN's top court to order Israel to stop its military offensive in Rafah in southern Gaza.
It is presenting its case at a two-day hearing at the International Court of Justice (ICJ) in The Hague. Israel is to deliver its response at the court on Friday.
South Africa is also seeking to force Israel to allow "unimpeded access" to Gaza for aid workers, journalists and investigators.
The court is already considering a case brought by South Africa in January accusing Israel of committing genocide against the Palestinians in Gaza. Israel rejected the claim as false and "grossly distorted".
Israel began its attack on Hamas in Rafah 10 days ago, amid warnings from the UN and others of a grave risk to civilians. More than a million displaced people had been taking refuge in Rafah and nearly 600,000 have fled from there since the start of the operation.
South Africa's application to the court accuses Israel of carrying out "genocidal" operations in Rafah and elsewhere in Gaza, and says that it "must be ordered to stop".
Addressing the court at the start of the hearing, South African barrister Vaughan Lowe KC said that "evidence of appalling crimes and atrocities is literally being destroyed and bulldozed, in effect wiping the slate clean for those who've committed these crimes and making a mockery of justice".
Israel says its offensive in Rafah is necessary in order to destroy the last remaining Hamas battalions which are based there and to rescue some 130 remaining Israeli hostages which it believes are being held there.
In January, in a highly charged case which was closely watched around the world, the ICJ ordered Israel to take measures to prevent potentially genocidal acts in Gaza. It also ordered Israel to do more to enable the provision of aid to the people there.
The then president of the court, Joan Donoghue, told the OceanNewsUK last month that the ICJ did not decide that there was a plausible case for genocide, but rather that the Palestinians had a right to be protected from genocide, as claimed by South Africa.
The ICJ is not expected to deliver a ruling on the genocide case for several years. Its rulings are legally binding, but in practice unenforceable by the court.
The latest application is the fourth which South Africa, whose governing party has a long history of solidarity with the Palestinian cause, has filed with the ICJ against Israel's actions in Gaza.
Israel began its offensive in Gaza after gunmen from the ruling Palestinian group Hamas launched an unprecedented attack on Israel on 7 October, killing about 1,200 people and taking 252 others hostage.
More than 35,270 people have been killed by Israel in the war in Gaza since then, according to the territory's Hamas-run health ministry.
