Dominic Nutt, of ACT member Christian Aid, said there were signs that fuel is running out, water supplies in the capital and elsewhere are intermittent, and there is a problem hidden from the public eye of internally displaced people who are living on people's floors, in basements and schools.

"It is impossible to be precise about the extent of the human crisis that is facing Lebanon," said Mr Nutt.

"This is not a tsunami where you can see the people who have been affected. By definition, these people are in hiding. They have run away from the bombing.

"Today, I met three families - 12 people in total including children as young as 18 months—living in a dank, humid, windowless basement. They were being helped by Association Najdeh*. They were lucky because they found this place after their homes were destroyed on the first day of the Israeli bombardment.

"This means they have a safe haven in which to stay, even though it is a horrific, soulless place, and they have been given clothes and will receive emergency rations from Najdeh.

"Many people are relying on charity and have been absorbed into the city by friends, neighbours and even strangers. Others are living in schools and parks and wherever they can."

Mr Nutt said there were rumours that fuel for both cars and for generators was running out, which would make matters worse.

Added to this, it has been reported that many people are stuck in their villages and aid workers are unable to reach them, including the United Nations agencies.

"Those that are left are either too old, too weak or to poor to move. And the Israelis are consistently not allowing aid workers to reach them.

"Thus, it is impossible to know how many people are in need and what they are in need of. Therefore, it is dangerous to attempt to predict the scale and type of disaster Lebanon faces. But it does face a disaster - and it will be a huge disaster when it comes."

*Association Najdeh is a partner of and receives funding from Christian Aid-ACT.