UK Prime Minister Tony Blair has spoken of his horror at the "global catastrophe" of the Asian tsunami.
Mr Blair said the tsunami's impact would be long lasting
Mr Blair, who is on holiday in Egypt, said the long-term effects would need attention from the international community for months, if not years.
The disaster has claimed the lives of 124,000 people, including 35 Britons.
His comments, made to Channel Four News, came as donations from the public to a disaster fund reached £60m, exceeding the government's £50m pledge.
Chief executive of the Disasters Emergency Committee, an umbrella group of leading charities, Brendan Gormley said: "This amazing generosity means the DEC agencies will be able to rebuild shattered lives and livelihoods."
The UN is pleading for the world's help
The government raised its initial contribution of £15m to £50m, making it one of the largest international donors.
Mr Blair said: "At first it [the tsunami] seemed a terrible disaster, a terrible tragedy.
"But I think as the days have gone on, people have recognised it as a global catastrophe."
He went on: "It is not simply the absolute horror of what has happened and how many people's lives have been touched.
"But it is also the fact that the consequences of this are not just short-term and immediate, but long-term, and will require a great deal of work by the international community for months, if not years, to come."
Mr Blair said he had believed from the beginning that the UN should be the lead agency in the relief effort, as "the proper clearing house".
He also paid tribute to the "remarkable" generosity of the British people in the aftermath of the disaster.
The Queen has also sent a message of thanks to British charity workers and those who have made donations.
Survivors fly home
A national three-minute silence in memory of the victims will be held on Wednesday.
On Saturday hundreds gathered for a service at Methodist Central Hall in London, at which 1,000 candles were lit in tribute to those caught up in the disaster.
Members of the congregation wept as images of the Boxing Day catastrophe were shown on large screens.
Of the 35 Britons confirmed dead so far, 29 died in Thailand, three in Sri Lanka and three in the Maldives.
On Saturday the Foreign Office chartered a British Airways 291-seat Boeing 747 jumbo jet from Thailand to the UK.
The plane, which landed at Heathrow at around 1645 GMT on Saturday, was carrying 94 evacuees, 11 of whom were from other European countries, and one body.
HOW TO DONATE
The Disasters Emergency Committee (DEC) is an umbrella group of UK charities including, among others, British Red Cross, Cafod, Oxfam, Save the Children, Tearfund
Call them on 0870 60 60 900 or donate online at www.dec.org.uk
By the end of the week people should be able to donate cash or cheques - made payable to the DEC Tsunami Earthquake Appeal - at High Street banks.
Cash or cheques (made payable to Post Office Ltd) can be donated over the counter at Post Office branches.
Other bodies raising money include the Muslim groups Muslim Aid (020 7377 4200) and Islamic Relief (0121 622 0622) and the Hindu charities Sewa International 0116 261 0303 and the ISKCON Disaster Appeal on 01923 856848.
Sri Lankan organisations including Asia Quake Relief Appeal UK (email firstname.lastname@example.org) are also raising money
A team of police, paramedics, doctors, nurses and Red Cross volunteers met the plane.
Survivor Charlie Anderson, 28, from north London, was in the water on a snorkelling trip near the Thai
resort of Krabi when the first of three waves struck.
"The boat went over my head. I remember the propeller flashing past my face, I was sucked right down to the bottom," he said.
He returned to the surface and was sucked down a further two or three times, before managing to get to a life jacket.
"Apart from nearly drowning, injury-wise I was all right," he said.
Speaking from the airport, Health Secretary John Reid said many volunteers had turned up to assist those returning, many traumatised, bereaved, and without their possessions.
Manufacturers and individuals had brought clothes and shoes to the airport to give to those in need, he said.
"The fact that there are people here today, giving up their New Year's Day, to help people who may have been bereaved or injured in this terrible disaster, I think is an indication of just how the whole British nation feels and has responded."
British charity Oxfam has appealed for an extra 10,000 volunteers to work in its shops to cope with the high volume of donations.
0207 008 0000 - for information on friends and relatives
0870 6060290 - for flight details or travel advice
The charity warned some shops might be forced to close temporarily if enough people did not come forward to help process the money being handed in.
The DEC is providing thousands of telephone lines for people to give donations to its Tsunami Earthquake Appeal - by calling 0870 60 60 900 - and they can also be made on its website.
The Foreign Office has set up an emergency helpline - 020 7008 0000 - for people worried about missing relatives.