Although as many as 500,000 people have left the border area, which has received the worst of the Israeli bombing, thousands remain.
In the village of Sreefa near Naqoura at least 21 people were confirmed killed and 60 missing after Israeli rockets hit 13 homes yesterday.
Nayla Mouawad, the Lebanese social affairs minister, said: "Sreefa has suffered a real massacre but we don't have enough details."
Although the current toll in Lebanon is above 300, it is likely to be higher, especially in the southern areas where bodies have not been recovered, doctors say.
Doctors and emergency services working in south Lebanon say it is extremely difficult to get access to the wounded because Israel has fired on Red Cross vehicles and civilian traffic.
Maha Mrouweh, a financial administrator at the Jabal Amal hospital in Tyre, told Aljazeera.net: "They are targeting the civilian cars. They are preventing the food from arriving in the south. They are preventing the Red Cross from arriving to the destroyed buildings. They are shooting the Red Cross."
Mrouweh said that none of the casualties being treated in the hospital was a Hezbollah fighter.
"No one is in Hezbollah, I assure you," he said. "All of them are civilians. Hezbollah soldiers are not being sent to the hospital. We don't see them. These are very secret people. The Israelis are just killing civilian people."
Ahmad Mrouweh, a doctor at the Jabal Amal hospital, said that he had received 20 bodies since the conflict had begun but many remained in the rubble of bombed houses or in burnt-out cars.
"There are bodies still lying in cars," he said. "It's a disaster. Nobody can reach the hospital because all the roads are cut."
Villages in the south are also running low on food supplies and medicines because supply trucks cannot find a way through.
Peter Bouckaert, emergencies director at Human Rights Watch, said: "Movement in southern Lebanon is extremely restricted even for international humanitarian organisations. The Israelis have refused to give guarantees that vehicles carrying supplies and wounded will not be targeted.
"I have worked in Iraq, Afghanistan and Kosovo and I have never seen a situation where humanitarian organisations have faced such access risks."
Mouawad said the southern areas had been worst hit, but central and northern areas of Lebanon were also struggling to cope with at least 100,000 refugees who have fled the south.
"We are living a humanitarian disaster … They are in a desperate situation. There is no milk, bread and medicine."
According to the Lebanese government, 21 infrastructure sites, 55 road bridges, two milk factories and two hospitals have been attacked in Israel's military offensive on Lebanon.
Mouawad said the Lebanese government was desperate for aid and asked for international assurances that relief supplies would get through to the affected areas.
"We are asking for a humanitarian corridor to the south and east of Lebanon," he said.
"If the international community do not react to help Lebanon then the Lebanese people will lose faith in them. The people of Lebanon deserve to live in peace and dignity."
Israel denies that it has been hitting civilians and says the official death toll is exaggerated.
Shimon Peres, the Israeli vice premier, said in an interview on CNN: "The numbers of the victims [in Lebanon] are not acceptable. We think that information coming from Lebanon is totally unreliable."