Anwar Abdul-Hadi, a senior member of the Palestinian Liberation Organization in Damascus, told the Ma'an News Agency Sunday an agreement had been delayed because of demands by the Free Syrian Army, the main opposition group in Syria. He did not reveal what the demands were.
There are an estimated 500,000 Palestinian refugees in Syria.
The Yarmouk camp, established decades ago, is the largest Palestinian refugee community in Syria.
Abdul-Hadi dismissed earlier reports that said an agreement had been reached. He said some PLO officials had made comments without securing guarantees for the return of the refugees.
Abdul-Hadi said the PLO demanded that all armed people, including Palestinian gunmen, withdraw from the camp.
The PLO also demanded that food and fuel be provided for camp residents and assurances be given that the camp will remain a neutral area, respected by all sides, Abdul-Hadi said.
Until the demands are met, the refugees will not be permitted to return, he said.
The camp has been the scene of heavy fighting, particularly last month, forcing refugees to flee to safety.
The Syrian army has imposed a blockade on the camp preventing the entry of food, fuel and medical supplies, sources told the news agency.