British Prime Minister Rishi Sunak will travel to Israel on Thursday before heading to other countries in the region in an effort to deescalate the Israel-Gaza conflict, his office has said.

"The attack on Al Ahli Hospital should be a watershed moment for leaders in the region and across the world to come together to avoid further dangerous escalation of conflict," Sunak said in a statement.

"I will ensure the UK is at the forefront of this effort."

Sunak will stress the international community must "not let Hamas' barbaric terrorism and disregard for human life become a catalyst for further escalation of conflict in the region", the statement said.

Expected in Israel early on Thursday morning, Sunak is due to meet his counterpart Benjamin Netanyahu and Israeli President Isaac Herzog.

He is also expected to insist that humanitarian aid, which London recently announced would be increased for the Palestinians, be allowed to arrive at a time when Israel has authorised the entry of aid into Gaza from Egypt, and that Britons stranded in Gaza be allowed to leave.

Alongside the British prime minister's trip, his Foreign Secretary James Cleverly is due to visit Egypt, Turkey and Qatar "in the coming days", according to Downing Street.

London has pledged its support for Israel following the bloody attacks by Hamas, which killed more than 1,400 people, and has announced that the UK's humanitarian aid to the Palestinians will be increased by a third -- an extra £10 million pounds ($12 million).

Israel is relentlessly bombing the small, crowded territory of Gaza, where more than 3,400 people have been killed, most of them Palestinian civilians, according to the local authorities.