The two leaders spoke by phone on Thursday afternoon with Sunak telling the Israeli leader that negotiating a humanitarian pause in the conflict that started on October 7 was an "immediate priority".

"The Prime Minister said the UK was deeply concerned about the loss of civilian life in Gaza and the potentially devastating humanitarian impact of a military incursion into Rafah," Sunak's spokesman said.

The call came after Israel launched a new wave of deadly strikes on southern Gaza on Thursday after vowing to push ahead with a "powerful" operation in the overcrowded city of Rafah despite growing international condemnation.

Netanyahu has vowed to crush militant group Hamas in response to its October 7 attack on Israel, which resulted in the deaths of about 1,160 people, mostly civilians, according to an AFP tally based on official Israeli figures.

At least 28,600 people, mostly women and children, have been killed in Israel's assault on the Palestinian territory, according to the health ministry in the Hamas-run territory.

Sunak told the Israeli leader that "more must be done" to ease restrictions on humanitarian supplies and ensure the UN and aid agencies could reach civilians in need throughout Gaza.

"He (Sunak) reiterated that the immediate priority must be negotiating a humanitarian pause to allow the safe release of hostages and to facilitate considerably more aid going to Gaza, leading to a longer-term sustainable ceasefire," Sunak's spokesman said.