Talks with Israel through mediators on further steps in a ceasefire agreement are conditional on Palestinian prisoners being released as agreed, Hamas official Basem Naim said on Sunday.

Israel said on Sunday it was delaying the release of hundreds of Palestinian prisoners it had planned to free the day before until militant group Hamas met its conditions.

Prime Minister Benjamin Netanyahu's office said that Israel was waiting to deliver the 620 Palestinian prisoners and detainees "until the release of the next hostages has been assured, and without the humiliating ceremonies."

That was a reference to recent handovers by Hamas that UN officials have said went against international law because they were not respectful.

Hamas has made hostages appear on stage in front of crowds and sometimes speak before they were handed over. Coffins with hostage remains have also been carried through crowds.

The Palestinian Prisoner's Society, a local group that supports Palestinian prisoners, said Israel is practising "state-terrorism against the prisoners and their families".

Ghasan Washahi, whose brother was set to be released on Saturday, said his family was disappointed with the delay.

"Every time there was a list of prisoners set to be released, we would wait, hoping Islam's name would be among them, but it was never there," he said, referring to his brother.

"My mother even started losing hope that he would be freed in the deal. And when his name finally appeared, Israel halted the deal." (Reuters)