ICRC representatives at the military checkpoint to the south of the camp say thousands of people are in need of treatment for chronic diseases such as diabetes, high blood pressure and kidney failure.
Since 20 May, when the Lebanese army besieged the camp and opened fire with tanks and artillery on positions held by suspected Fatah al-Islam militants, there has been no electricity in the camp, meaning medicines such as insulin cannot be preserved in standard fridges.
The UN Palestinian relief organisation, UNRWA, says just over 5,000 families, around 25,000 people, have now been displaced from Nahr al-Bared, leaving an estimated 15,000 people, according to estimates by Palestinian committees inside the camp, which put the original total population at around 40,000. A 2004 survey of the camp's population by the Palestinian Popular Committee (PPC) put the figure at just over 31,000.
The ICRC said a PPC study in Nahr al-Bared showed the camp had one of the highest rates of cancer per person in the Middle East, and many sufferers are in need of life-saving treatment currently not available to them.
In February the ICRC completed an assessment of access to health facilities for Palestinians in most of Lebanon's 12 camps, where over half the 400,000 Palestinian refugees live. At Nahr al-Bared the survey found nearly 30 percent of people with heart disease, 17 percent with neurological diseases such as epilepsy, and 16 percent with diabetes, according to Micheline Sarkis, field officer for ICRC Beirut's health department.
"It is frustrating not to have unfettered access to the camp to deliver aid, but we continue to make contact with all parties. The situation is extremely volatile," Jordi Raich, head of the ICRC delegation in Lebanon, told IRIN.
The ICRC said it was assessing whether to buy the necessary medication locally or import it from Geneva in a few days.
ICRC aid deliveries
On Sunday, the ICRC delivered 14 tonnes of food, three tonnes of bread, and 20,000 litres of water to Nahr al-Bared after receiving permission to access the camp through the PRC. The agency had sent an 11-truck convoy, stocked with 200 tonnes of food, from its regional office in Amman which had been waiting to access the camp for two days.
The ICRC on Saturday delivered 22,000 litres of water and two tonnes of food, enough for 1,200 people for one day, and 4,000 candles to the Palestinian committees operating inside the camp, the second aid delivery it has made into Nahr al-Bared since the start of the crisis on 20 May. On Friday the ICRC delivered 17,000 litres of water.
The agency has so far delivered 70 tonnes of food to Beddawi refugee camp, 10km away, where most of the estimated 25,000 displaced Palestinians from Nahr al-Bared have fled.
UNRWA, which has launched an emergency website (http://www.unrwa-lebanon.org/nle) to inform the public about its response to the crisis, has trucks loaded with 4,000 bundles of bread, 58,000 litres of water and 2,000 food parcels (each containing provisions for one family and sufficient for 30 days) but is waiting for clearance to enter Nahr al-Bared camp.
Over the weekend, the agency distributed 4,000 mattresses, 3,500 pillows, 3,500 blankets and 1,040 hygiene kits to displaced refugees in north Lebanon, as well as to those who have fled south to Beirut, Sidon, Tyre and east to the Bekaa Valley.
UNRWA is also providing water and sanitation services in Beddawi camp. The director of UNRWA in Lebanon, Richard Cook, said on Sunday that one of the agency's Palestinian employees was killed on Tuesday. He said conditions in the camp were "very serious and very poor" because the water, sewage and electricity systems were not functioning.
The PRC, the only emergency service running ambulances into Nahr al-Bared was unable to access the camp all day on Friday, but on Saturday made deliveries of food, water and medical supplies from four ambulances, and also brought out permanently disabled camp residents.