A social worker says the first she knew of Moko Rangitoheriri being abused by his carers was the night before he died.

The three year old died after two months of extreme abuse at the hands of Tania Shailer and David Haerewa in 2015.

A Coroner’s inquest into the brutal death of three-year-old Moko continues today, to figure out how he ended up in the care of his killers Tania Shailer and David Haerewa.

Former Taupo Maori Women’s Refuge worker Trina Marama has told a Coroner's inquest she thought any bruises on children in Shailer's care came from sibling rivalry.

Ms Marama says the night Moko was put in hospital, his sibling stayed with her and told Ms Marama about the first time she heard Shailer hit Moko.

She said that was the first time she'd ever been told of any adult abusing a child in that family. She added that Tania had told her she wasn’t coping looking after him.

Trina Marama worked with Shailer and one of Moko’s siblings, to help deal with sibling violence within the household.

She had been told that Tania wasn't coping with the two extra children and as a result was told they would make an appointment with Child Youth and Family Services. It was during that visit, Tania aired her concerns the children be returned to their mother and father.

The inquest continues.