British experts are helping co-ordinate the international response to the deadly earthquake in Indonesia.
A team of five advisers arrived in the capital Jakarta on Tuesday and another humanitarian specialist has been deployed to the country.
More than 1,300 people are feared to have died after a magnitude 7.5 earthquake and tsunami struck on the island of Sulawesi on Friday.
Hundreds more were injured and thousands have been left homeless.
International Development Secretary Penny Mordaunt made an initial £2 million of UK aid available for the relief effort.
The British experts will assess the situation and decide if further support is needed.
Some of the team hope to go to affected areas including Palu – the largest city that was heavily damaged.
Save the Children has warned that survivors are facing growing health risks with an increasing chance of disease outbreaks.
The charity said clean water supplies are running low and thousands of families are living in “makeshift shelters and cramped evacuation centres”.
Tom Howells, programme implementation director, described the situation as “a recipe for disaster”.
“There is debris and rubbish everywhere, and it’s difficult for families to maintain hygiene standards, quite apart from getting access to food and clean drinking water for children and babies.
“We’re really concerned that we could start seeing a growing number of children getting sick with illnesses like diarrhoea.
“The destruction and loss are absolutely heart-wrenching, and the suffering on a scale that’s hard to fathom. It will be a long recovery process.”
The government of Indonesia is leading the response and more than 25 other countries have offered assistance.
Blankets, sleeping mats, water containers and ambulances are being sent to the worst-affected areas as part of the relief effort.
UK aid is already supporting relief efforts through funding to the International Red Cross and Red Crescent, which has 175 volunteers and staff on the ground.