Residents of the refugee camp of Bureij arrive in Deir Al Balah following an evacuation order on Friday. AFP

In the evacuation order, the Israeli army instructed residents in the Bureij refugee camp and surrounding areas to "leave immediately for their own security" and head towards Deir Al Balah city further south.

"People in Gaza are people. They are not pieces on a checkerboard — many have already been displaced several times," Thomas White, Gaza director for the UN's agency for Palestinian refugees, UNRWA, wrote on social media.

"The Israeli army just orders people to move into areas where there are ongoing air strikes. No place is safe, nowhere to go."

After the evacuation order, thousands of Palestinians fled the central Gaza Strip to the south on Friday.

UNRWA tweeted that the latest order would affect more than 150,000 people. An estimated 1.9 million have been displaced by the war, according to the UN.

Thomas White says “nothing has changed” in the besieged enclave since the UN Security Council passed a resolution on Friday evening to boost aid, Al Jazeera reports.

“People continue to be pushed around Gaza into an increasingly smaller space; aid trucks alone are not going to solve that problem. We have Rafah right now — a city that normally has 280,000 people — hosting a million people,” White said.

He reiterated the need for a ceasefire to end the suffering of civilians, hundreds of thousands of whom are living in the open, as “air strikes continue to hit all parts of Gaza.”

'THEY BOMB DAY AND NIGHT'

Israel has long urged residents to leave northern areas of Gaza but its forces have also been bombarding targets in central and southern parts of the tiny coastal enclave.

"They ask people to head to (the central Gaza city of) Deir Al Balah, where they bomb day and night," Ziad, a medic and father of six, told Reuters by phone. Palestinian mourners attended the burial of a family of four killed in an Israeli airstrike on Khan Younis in southern Gaza.

"International law has collapsed... If Israel were in the Palestinians' position, the world would not stand still and would act," said Ramzy Aidy, a Gaza resident with a doctorate in law.