More than 900 trucks carrying humanitarian aid entered Gaza on Monday, the United Nations said, exceeding the daily target outlined in the ceasefire agreement between Israel and Hamas.

"Humanitarian aid continues to move into the Gaza Strip as part of a prepared surge to increase support to survivors," the UN's humanitarian office (OCHA) said.

"Today, 915 trucks crossed into Gaza, according to information received through engagement with Israeli authorities and the guarantors for the ceasefire agreement."

Throughout the conflict in Gaza, the UN has denounced obstacles restricting the flow and distribution of aid into the battered Palestinian territory.

On Sunday, the day the ceasefire came into force, 630 trucks entered Gaza.

An initial 42-day truce between Israel and Hamas is meant to enable a surge of sorely needed aid for Gaza after 15 months of war.

The ceasefire agreement calls for 600 trucks to cross into Gaza per day.

Meanwhile, Hamas said on Monday it would next release hostages held in Gaza on Saturday, after an official with the Palestinian militant group had said they would be released a day later than expected.

Hamas is set to release more than 90 hostages over the coming weeks as part of the ceasefire deal. (Agencies)