A volcano erupted on Wednesday in the same central Indonesian island where at least 1,407 were killed following Friday's disaster.
Tearfund's Head of Humanitarian Support, Oenone Chadburn told Premier's News hour the latest from their partners on the ground.
"We certainly know from pastors that we've spoken to...they're still looking for families and congregations as well as their neighbours," she said.
"We are hearing that people are having to bury their own dead which will be a heart-breaking situation for them."
Rev Krise Gosal is in Palu - the worst affected coastal city.
He explained: "Survivors are hungry and need clean water to drink. Babies are crying for milk.
"We are asking our church networks to share the burden of the sufferings by donating food, tents and other supplies as well as funds.
"Churches in Indonesia are uniting with one heart to express their solidarity with the people in Palu, Donggala, and Sigi."
Mount Soputan in North Sulawesi province spewed ash nearly 20,000ft into the sky, although there have been no evacuation orders so far.
A government volcanologist said it is possible the eruption was accelerated by the 7.5 magnitude earthquake which struck Central Sulawesi five days ago.
Tearfund's partners have also deployed medical teams to the affected areas which include emergency doctors and nurses and an orthopaedic surgeon. Another team will include a midwife.
Listen to Premier's Eno Adeogun speaking with Oenone Chadburn from Tearfund:
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