British charities are launching a radio and TV campaign to raise funds for victims of the devastating floods in north-western Pakistan.
The Disasters Emergency Committee (DEC) - an umbrella organisation of 13 UK humanitarian aid agencies - will broadcast the appeals later.
The UN says three million people have been affected by the floods, with at least 1,400 killed.
People can also donate by post, text message, at the Post Office and banks.
The TV and radio appeal will be presented by journalist and former British hostage in Lebanon, John McCarthy.
The aid organisation, Doctors of the World, has been working in Pakistan for nearly 15 years, based on the outskirts of the worst-affected area.
Its director, Susan Wright, described some of the difficulties the aid money would be used to tackle.
She said: "After the flooding there's the initial, unfortunate, but expected deaths that come from the flooding itself.
"Then there is... a kind of second wave of problems. Those have to do with people fleeing the area very quickly, often they are people who are not in the best health and haven't eaten, haven't had water for quite some time. So there's injuries often sustained while they are travelling.
"Then, as we've heard quite a bit about, the fear of outbreaks. In this case cholera is quiet common in this kind of situation.
"So we have to do what ever we can to work with water purification systems - and that's the great irony of flooding: that it causes these kinds of problems and yet there's this very difficult access to clean water."
There have been reports of cholera cases in the Swat Valley.
Further rain slowed the relief effort in on Tuesday as aid agencies struggled to reach the thousands of people cut off by the floods, which hit the north west of the country hardest.
They have warned hundreds of thousands of people are awaiting help and there are shortages of food, clean water, shelter and medicine.
Director of Policy at Save the Children, David Mepham, said people were using "ingenious" ways to get help through, including using helicopters, boats and donkeys.
He added that people could "feel very confident" their donations would be used to assist those affected.
In some affected areas, there were protests at the government's perceived inaction. The Pakistan army has defended its rescue operation.
Despite demands for him to return to Pakistan, President Zardari is pressing ahead with his schedule of diplomatic visits to European nations.
Mr Zardari has also been snared in an open disagreement with David Cameron over his country's commitment to fighting terrorism and the Taliban.
The United Nations estimates 980,000 people have lost their homes or have been forced to flee, while the UN World Food Programme said some 1.8m needed food aid.
The DEC charities are Islamic Relief, ActionAid, Age UK, British Red Cross, CARE International, CAFOD, Christian Aid, Concern, Merlin, Oxfam, Save the Children, Tearfund and World Vision.
- ActionAid is working with its partners to help more than 23,000 people in the Punjab areas of Kot Adu, Layyah, Khoshab and Bhakar to distribute food including rice, sugar, pulses, oil and tea. Twelve medical camps have been set up there. In Azad Jammu Kashmir and Khyber Pakhtoonkhwa - which includes hard-hit areas of Swat and Swabi - it is providing sheets, mattresses and mosquito nets to displaced survivors.
- The British Red Cross has released £50,000 from its disaster fund to provide immediate relief. With the International Federation of Red Cross and Red Crescent Societies, it is supporting the Pakistan Red Crescent to help 35,000 people by distributing food and other supplies and working to provide water and sanitation.
- CARE International has sent 11 trucks of emergency supplies to Khyber Pakhtunkhwa including shelter for about 1,800 people, hygiene kits, kitchen sets and water purification tablets. It has set up eight mobile health clinics and is due to send shelter and supplies to other districts.
- Christian Aid is working with its partner agencies to provide food shelter and medical assistance to 50,000 people
- Concern has been carrying out assessments with local partners and is providing clean water, food, shelter, mosquito nets, hygiene and kitchen items and emergency medical help. It reached 400 families on Tuesday and hopes to help 10,000.
- World Vision has distributed relief supplies to more than 7,000 people and will continue to deliver them in coming days. It hopes to help long-term recovery in the area.
The DEC's automated donation line is 0370 60 60 900 and the website is www.dec.org.uk.