South Africa said on Tuesday it had asked the world's top court to consider whether Israel's plan to extend its offensive in Gaza into the city of Rafah requires additional emergency measures to protect Palestinians' rights.

The International Court of Justice (ICJ) last month ordered Israel to take all measures within its power to prevent its troops from committing genocide against Palestinians in Gaza, in a case brought by South Africa.

Israel has denied all allegations of genocide in connection with its war against Gaza's ruling Palestinian Islamist group Hamas and asked the court to reject the case outright, saying it respects international law and has a right to defend itself.

Israel has said it is planning to expand its ground assault into Rafah, where over 1 million Palestinians have sought refuge from the offensive that has laid waste to much of the Gaza Strip since Hamas militants attacked Israel on October 7.

"In a request submitted to the court on Monday, the South African government said it was gravely concerned that the unprecedented military offensive against Rafah, as announced by the State of Israel, has already led to and will result in further large-scale killing, harm and destruction," a statement issued by South Africa's presidency said.

"This would be in serious and irreparable breach both of the Genocide Convention and of the Court's Order of January 26."

The Hague-based ICJ declined to comment on whether it had received the request.

In past cases, the ICJ has sometimes granted additional emergency measures when circumstances on the ground changed.

The court has not yet ruled on the core of the case brought by South Africa - whether genocide has occurred in Gaza. But it recognised the right of Palestinians in Gaza to be protected from acts of genocide.