A childcare provider says it is "devastated" after a three-year-old boy was found dead in a minibus at Edmonton in the south of Cairns.

Key points: A minibus driver found the boy, 3, dead inside the vehicle on Tuesday afternoon

A minibus driver found the boy, 3, dead inside the vehicle on Tuesday afternoon Police said they were investigating what had happened after the boy should have been delivered to day care that morning

Police said they were investigating what had happened after the boy should have been delivered to day care that morning They could not confirm if he had been left in the minibus during the day

Queensland Police said the minibus driver discovered the child's body inside the Goodstart Early Learning vehicle, which was parked out the front of Hambledon State School on Stokes Street, at 3:15pm on Tuesday.

Police said the minibus picked the boy up from his home on Tuesday morning, but could not confirm if he had been left in the vehicle throughout the day.

Detectives from the Child Protection Investigation Unit in Cairns are investigating the circumstances surrounding the incident and remain at the scene.

"We're just trying to work out exactly what's happened between now and when he should have been delivered to the day care centre," Inspector Jason Smith told Channel Nine.

Police will prepare a report for the coroner. ( ABC News: Mark Rigby )

"The death of any child is an awful thing, which is why it is so important for us to get to the bottom of this," he said.

In a statement, Goodstart Early Learning said it was "devastated by the death of a child in our care in Cairns earlier today".

"We are working to support the entire centre team, our families and our children.

"The matter is now a police investigation and we will be working with the police, Department of Education (childhood education and care), and Workplace Health and Safety.

"Our thoughts are very much with the family of the child at this time."

Police said the boy's mother had been notified and a report would be prepared for the coroner.