The church where more than 80 Indonesian children were studying the Bible has moved about two kilometres from where it stood on Friday last week, before disaster struck.

A 7.5 magnitude earthquake that struck the west coast of Sulawesi island caused extensive soil liquefaction, a phenomenon that turns the ground into a liquid mire that can flow and skid buildings across the land, and pull victims under.

Bodies of 35 of the children – both boys and girls studying at the 'Warrior of God' Bible camp – have been found.

On Monday, dozens of rescue workers, some using an excavator, were searching for 52 of their class mates.

'I'm not angry, what for?' said Martin Kebo, the father of one of the missing children.

'We only hope, as a community, that the victims are found. But it's been five days and they've only sent out an excavator today.'

Kebo said he had been searching for his son, Tegar, though the tangled debris and slowly drying mud, for 12 hours every day since Friday.

'My neighbours said: "Your son hasn't returned" and I said: "Yes, what can I do? God loves him more."'

The official death toll from the 7.5 earthquake and tsunami waves it triggered rose to 1,407 on Wednesday, among them the 35 children whose bodies have been recovered.

Officials fear the toll could soar, though many of the estimated hundreds of victims of soil liquefaction might never be found.

The Jono Oge church and Bible camp are just south of the small coastal city of Palu, which was hard hit by the earthquake and tsunami waves that crashed into its shorefront.

Indonesia has the world's largest Muslim population but also pockets of Christians scattered across its many islands. Lying on the west coast of the island of Sulawesi, Palu is 1,500 km (930 miles) northeast of Indonesia's capital, Jakarta.

'Such perfection'

The two-storey church used to stand about 11 metres (36 feet) high, an electrician who did work for the church told a visiting Reuters news team.

Now its ruins – or half of them – stand just over 1 metre high, about two kilometres from its original spot. The other half of the church sticks out of the mud about 500 metres away.

The children were aged about 17, students from the SMA Negeri 2 Palu, a city high school.

Remnants scattered in the mud tell a story of mundane detail and faith.

The students would have been having dinner when the earthquake struck in the early evening, according to a camp timetable found by Reuters.

They were later scheduled to play 'small games', followed by 'movie time' before bed.

Religious texts with titles such as 'Water of Life', 'Moment of Peace' lay strewn among notebooks and Bibles.

A photograph of more than 40 smiling students in gray and white uniforms bore the words 'Shalom Bible Camp Edition'.

A diary with the name Julitha and only one entry, neat slanted handwriting, dated August 8, 2018, reading:

'God has created this earth in such perfection and everything has been determined.'

'Everything has its place, be it in the sea, on land or on air.'

It was not known if Julitha was among the missing or dead.