The European Union said today it will not be easy to set up a system that will give money to the most needy Palestinian.
"We will need some time. It is not that easy. It is a complex task," European Commissioner for External Relations Benita Ferrero-Waldner said in an interview.
Under a plan agreed by the Quartet of Middle East mediators - the European Union, the United States, United Nations and Russia - money would start to flow starting next month to pay "allowances" to Palestinian doctors and nurses.
The aid would bypass the Hamas-led Palestinian government, which faces an international aid boycott over its refusal to recognise Israel, renounce violence and accept past interim peace agreements.
But a centrepiece of the plan - proposed allowances for the neediest Palestinians - will not get under way until a system is in place to determine who is eligible to benefit and to ensure that all of the money is spent as intended.
"There we still have to work out all the details," Ms Ferrero-Waldner said. She said talks would begin on Monday with the World Bank on developing a set of criteria to determine eligibility for the so-called "needs-based allowances".
Western diplomats said it could take several months to get the system in place. Some 165,000 Palestinian government employees have gone unpaid for the past three months.
Hardship has deepened in the occupied West Bank and in Gaza amid inter-factional violence.