An appeal to help hundreds of thousands of people who have fled their homes in Gaza is being launched by the Disasters Emergency Committee.

The DEC, which brings together 13 leading UK aid charities in "times of crisis", said half a million people have been forced from their homes, while up to 1.5 million have no access to water, sanitation or medical care.

The current ceasefire between Israel and Hamas is the longest lull in a war that has killed nearly 1,900 Palestinians so far, 75% of them civilians, according to the United Nations. Israel has lost 67 people, including three civilians.

All of the UK's main broadcasters have agreed to show the television appeal, which will be screened tomorrow, the DEC said.

In 2009, the BBC and Sky News refused to broadcast the DEC's appeal to tackle the humanitarian crisis in Gaza, claiming it would compromise their impartiality in reporting the conflict.

But both networks as well as ITV, Channel 4 and Channel 5, who broadcast the 2009 appeal, have accepted the latest film meets the DEC's "appeal criteria", the charity body said.

Brendan Paddy, head of communications at the DEC, said: "We've made the case to all broadcasters that our appeal criteria had been met and all have agreed and have said they will carry the appeal."

DEC chief executive Saleh Saeed said the humanitarian emergency is affecting "virtually every man, woman and child in Gaza".

He said: "After four weeks of terrible fighting Gaza is on the edge. Over half a million people have been forced from their homes, and one and a half million people have no or very limited access to water or sanitation.

"Many people are living in terribly overcrowded UN shelters, but they still need food and basic household items which we take for granted. Many are in urgent need of medical care, but hospital supplies are almost finished.

"Even before the conflict began, the people of Gaza were close to breaking point. Now we are seeing a humanitarian emergency affecting virtually every man, woman and child in Gaza. The DEC's member agencies and their partners are on the ground but they need funds to meet the huge needs.

"They are relying on the generosity of the British people to make a difference in Gaza."

Although the truce between both sides is only temporary, 11 DEC member agencies are currently supporting work or planning to work inside Gaza, with many "rapidly increasing" their level of assistance.

Some agencies have worked through the fighting despite the considerable risks involved and others have responded when and where lulls in the fighting allow, the DEC said.

So far Oxfam has delivered safe water to up to 175,000 people per day and the British Red Cross partners are supporting emergency medical services.

Donations are already being received: £25 can buy 150 bandages, £50 can feed five families for a day and £100 can provide an emergency shelter kit and blankets for one family.

To make a donation to the DEC Gaza Crisis Appeal visit www.dec.org.uk, call the 24-hour hotline on 0370 60 60 900, donate over the counter at any high street bank or post office, or send a cheque. You can also donate £5 by texting the word SUPPORT to 70000.