Leader of the British opposition Ed Miliband has said the Labour Party is against Israel's ground invasion of Gaza.

"We oppose the Israeli incursion into Gaza," he told the Huffington Post after meeting US President Barack Obama and National Security Adviser Susan Rice at the White House.

"I don't think this will make the situation better. I fear it will make it worse," he added.

Miliband, the Labour Party's first Jewish leader and a strong supporter of the state of Israel, said the country's air and ground offensive in Gaza will likely aid Hamas' recruiting efforts and would worsen Israel's standing in the eyes of the international community.

He also criticised the loss of innocent Palestinian lives in the Gaza Strip. According to the Gaza health ministry, 604 Palestinians have been killed by Israeli air strikes and charity Unicef claims almost a third of those are children. In contrast, 29 Israelis have been killed, 27 of whom were Israel Defence Forces soldiers.

"As a party we oppose the further escalation of violence we have seen with Israel's invasion of Gaza," said Miliband.

"I defend Israel's right to defend itself against rocket attacks. But I cannot explain, justify or defend the horrifying deaths of hundreds of Palestinians, including children and innocent civilians."

The politician, a strong contender to become the next British prime minister, warned a viable peace process is needed to prevent more outbreaks of conflict between Israel and Hamas.

"What this horrendous, terrible last few weeks has shown is the vacuum of not having a process is incredibly dangerous," he said.

"That vacuum means any restraint breaks down. And so you've got to restart a [peace] process."

Miliband lent his support to the two-state solution and said that he believed Israeli Prime Minister Benjamin Netanyahu also supported this solution despite recent comments that suggest otherwise.

"I read his public statements about the two-state solution as important. He said he's in favour of a two-state solution," Miliband said. "I genuinely believe there is not another possibility."

He proceeded to criticise the continual building of Israeli settlements on Palestinian land, saying that such acts would threaten any process.

"I am concerned that the more settlements there are, the more the growth of settlements can become a problem" in relation to the peace process.

Both US Secretary of State John Kerry and UN Secretary-General Ban Ki-moon have arrived in Cairo as the international community clamours to achieve a ceasefire on the conflict.