A UN special rapporteur has said the humanitarian situation in the Palestinian territories has worsened seriously because of the aid boycott.
The UN says food and medical supplies are in short supply
The international freeze in aid followed the victory of the Hamas militant group in January.
John Dugard, who visited the territories recently, likened the boycott to economic sanctions.
The EU, the largest donor to the Palestinian Authority, and the US are demanding that Hamas renounce violence.
Hamas is also being asked to recognise Israel and acknowledge all past agreements signed between Israel and the Palestinians. The militant group still calls for the destruction of Israel.
Israel has also blocked the transfer of more than $50m (£27m) in monthly tax revenues it collects on behalf of the Palestinians.
On Monday, EU officials announced a plan under which Palestinians could begin to receive direct emergency aid by the beginning of July.
Under the plan the EU will give 100m euros ($126m, £69m) but will bypass the Hamas-led Palestinian government.
Mr Dugard is the UN's human rights rapporteur for the Palestinian territories. Special rapporteurs are appointed by the UN secretary general to investigate particular issues, but are independent of the organisation.
He said the aid boycott was causing ordinary Palestinians to lose faith in the international community.
He described ordinary people in the Palestinian territories as traumatised. Medical services were in short supply, he said, so too was food.
The growing restrictions on movement caused by Israel's security barrier were partly to blame, Mr Dugard said, but the biggest factor was the economic freeze imposed by the international community.
The Rafah crossing is monitored by Palestinian and European guards
As a result of the aid freeze, Mr Dugard said, the quartet of Middle East negotiators made up of the United States, the European Union, the United Nations and Russia, was losing credibility among Palestinians.
"The quartet has made it virtually impossible for the Palestinian Authority to meet its responsibilities in respect of medical supplies and other services," he said.
"The quartet seems to have changed its policy from that of peace facilitator to policeman."
Mr Dugard said the quartet was in danger of becoming so discredited that it might be better for the UN and the EU to withdraw from it altogether.
"The Palestinian people have been subjected to economic sanctions, the first time that an occupied people have been so treated," Mr Dugard said.
He admitted it was important for Hamas to renounce violence and recognise Israel but, he added, compulsion was unlikely to achieve that goal.
Instead Mr Dugard called for what he described as creative diplomacy.
Since neither Hamas nor Israel was blameless, he said, it was time for the UN and the EU to look for ways to bring both sides to the negotiating table.
In a separate development, the Israeli army has re-opened the border crossing between the Gaza Strip and Egypt, several hours after it was closed because of a security alert.
The crossing at Rafah is Gaza's main gateway to the outside world.
It had opened briefly on Thursday after a two-day closure.
The Hamas-led Palestinian government this week accused Israel of using the closures to inflict even more hardship on the Palestinian people.
European monitors are deployed at the Rafah border terminal under an American-brokered deal, aimed at reviving Gaza's economy following Israel's withdrawal last year.