British rescue workers are continuing the hunt for survivors two days after the South Asia earthquake, which has so far killed more than 19,000 people.
Search teams are aiding the effort in Pakistan's capital Islamabad and rural Kashmir, while Oxfam has sent engineers to help the sanitation effort.
Meanwhile, an umbrella group of 13 UK charities is considering whether to launch a joint appeal for donations.
The government has so far pledged nearly £1m to the relief operation.
"And as we respond to the requests for help then the sum that we commit will rise," said International Development Secretary Hilary Benn.
He said the government was also providing vital practical help on the ground, as well as tents and blankets to protect survivors from the "very cold nights".
"These are some very remote regions where transport is difficult and we are all working flat-out to try and get help to people who need it."
The government will also fund the transportation of any supplies from the UK, or anywhere else, that charities need to send.
Meanwhile, the Ministry of Defence has offered assistance to Pakistan's government and was awaiting an answer, said a spokeswoman.
The Archbishop of Canterbury, Dr Rowan Williams, has sent a message to church leaders in Pakistan and India, saying "our thoughts are very much with you".
Umbrella organisation the Disasters Emergency Committee will decide whether to set up a joint appeal if certain criteria are met.
In a conference call between all its 13 charities, they must decide if they believe a public appeal would be successful and whether they can provide swift assistance.
A spokesman for Oxfam said they already had people on the ground. "Another rescue team is arriving in Abbottabad in Pakistan today, and we're sending public health and water engineers," he said.
UK GOVERNMENT FUNDING
£100,000 "petty cash" for relief teams flying to the region
£230,000 on the deployment, support and return of search and rescue teams
£130,000 to the World Health Organization appeal for health and trauma kits
A £446,000 contribution to a European immediate response fund
"Some will be going to Kashmir, but others will be staying in Islamabad to co-ordinate the international effort for water and sanitation."
In Muzaffarabad, the capital of Pakistan-controlled Kashmir, Willie McMartin - team leader of the International Rescue Corps - said the situation was desperate.
The Stirlingshire-based group was flown into the remote region by helicopter.
"We have been told by the locals that anything up to 50% of 30,000 people in the area are actually dead and certainly the people are in the street, they won't go into houses," he told the BBC.
It is estimated up to 1.5 million Britons have links to the area hit by the 7.6-magnitude quake which struck Pakistan, Afghanistan and northern India on Saturday morning.
It is also thought to have injured more than 42,000.
Jehangir Malik, national fund-raising manager for the charity Islamic Relief, said there had been a massive response to their appeal for donations.
"We have had loads of calls from people asking how they can help, their generosity has been overwhelming once again," he said.
The British High Commissioner in Islamabad Mark Lyall Grant said the British relief effort was one of the largest with 29 search-and-rescue people on the ground in Islamabad and 40 in Muzaffarabad.
British teams include workers from Rapid UK, who have been involved in the rescue effort at a collapsed apartment block in Islamabad from which five survivors have been pulled.
Rapid UK's Tony Holland said conditions were taxing and stressful.
"When you look at the blocks of flats that are around it and you think how low it's gone, there are lots and lots of voids in there, and I think there is quite a strong chance of more survivors."
Two aid flights have left the UK and the government has pledged funds as they are needed, plus medics, staff and aid workers.
But the government's aid package has been criticised as "measly" by the Muslim Association of Britain.
It said the disaster compared "with the tsunami tragedy in December of last year and requires an equal response in terms of momentum and size".
FOREIGN OFFICE INFORMATION
Charity appeals have already been launched by the British Red Cross, Oxfam, Unicef, Islamic Relief and Muslim Aid, with Oxfam reporting around £50,000 generated within the first hour alone.
Oxfam estimated it would spend £4m on its relief effort, expecting to help 300,000 people.
Sir Iqbal Sacranie, secretary general of the Muslim Council of Britain, said he had been hearing from hundreds of UK families who have discovered their close relatives have suffered from the tragedy.
"So it is not people in another part of the world - they are their own ones who are suffering. It is much closer to home," he added.