While little Moko's mother was tending her eldest child in hospital, the three year old's carers were routinely and savagely beating him to death.

Moko Sayviah Rangitoheriri's mother was unable to have her children with her at Starship Children's Hospital and so asked David Haerewa and Tania Shailer, who have four children themselves, to mind Moko at their Taupo home.

Haerewa, 43, and Shailer, 26, appeared in Rotorua High Court on May 2 to plead guilty to manslaughter charges. The pair had initially pleaded not guilty to a charge of murder. Hawera stood stoic, head down, while he gave his plea. Shailer looked straight ahead.

MATT SHAND/FAIRFAX NZ Tania Shailer, 26, and David William Haerewa, 43, pleaded guilty to manslaughter at the Rotorua High Court.

Moko's family observed the pair through teary eyes.

The summary of facts for the case paints a grisly picture of Moko's last days. During the two months he was with Haerewa and Shailer, he was kicked, thrown, dropped face first on the floor, bitten, stomped on, had faeces rubbed on his face and was denied medical care.

The abuse only came to light after his little body could take no more punishment. On August 10, 2015, Shailer called for an ambulance after Moko became unresponsive. She said Moko was very cold, not breathing and his stomach was hard. She said Moko had fallen from a woodpile.

Paramedics arrived to find Moko lying face down in the home's hallway. Shailer was by his feet while Haerewa kept the other children away from the paramedics. Ambulance officers realised Moko's condition was dire. All they could do was scoop him up and rush him to Taupo Hospital.

He arrived with swelling to his face so bad it was impossible to open his eyes. His abdomen was distended. He had bruising on his front and back. Multiple abrasions and wounds that appeared to be human bite marks were found on his face and arms.

Starship Hospital was called at 3.45pm and plans were made to move Moko north to the hospital where his mother and sibling already were.

It was a journey he would not make.

He could not be revived and was pronounced dead at 10pm. Shailer asked hospital staff if Moko would have survived had medical attention had been sought earlier, the summary of facts says.

A homicide investigation began and a post-mortem was undertaken. It was difficult to determine the exact cause of death due to the number of injuries. Lacerations and a haemorrhage deep within Moko's abdomen, coupled with a bowel rupture - likely caused by being stomped on by Shailer - was one potential cause. The other cause of death could have been swelling to the brain from repeated blows to the head.

His injuries included facial and neck contusions and abrasions; human bite marks on the left cheek, right cheek and arms; lacerations to his chin, neck, ears and lip; haemorrhages to both eyes; and multiple abrasions and contusions over the skin of his chest and abdomen. His bowel was also ruptured, causing infections, making him very weak.

Both defendants supported each other's attacks on Moko and the "culture of violence" that occurred within the home, the summary of facts says. The viciousness increased over time. Shailer was observed by a witness biting Moko and Haerewa admitted to continually attacking Moko. He said it became routine to pick on Moko and he didn't want him around him.

Two of the child witnesses said it was Shailer who stomped "really, really hard" on Moko's abdomen and stomach. It was after this act, thought to have occurred on Thursday, August 6, 2015, that Moko's body starting rapidly giving out.

On that Thursday, Moko was soiling himself uncontrollably. By the Sunday, Moko could barely walk. He started falling to the ground, was vomiting often and was unable to stop defecating. Both Shailer and Haewera were at home the entire day with Moko, but no medical treatment was sought. Haewera kicked Moko in the back after he defecated on this day. Shailer held his mouth shut to silence him.

On Monday, August 10, Moko was unable to speak and could barely move. His stomach became hard. Breathing was laboured. Shailer walked her children to school and at midday went to attend a course. On her trip home about 2.20pm, she told a friend Moko had fallen from a woodpile. Her friend was concerned and said it was best to have him checked out in case he had a head injury. She even offered to drive them to the hospital. Shailer declined.

Forty minutes later, she would make the 111 call that brought their violence to light, but it was too late to save three-year-old Moko.

Shailer at first said Moko's injuries were a result of Moko doing things to hurt himself, the summary of facts says. She said Moko had fallen from the bunk bed. She said he would rub his neck against the table and even run into the walls head first. She also said Moko had pleaded with her not to take him to hospital after he had "fallen off the woodpile".

At that time, Moko was unable to walk, let alone say anything.

His killers will be sentenced on June 27 in Rotorua High court at 10am.

In October last year, Shailer and Haerewa failed to keep their names suppressed at hearings in the Rotorua High Court.

They pleaded not guilty to the murder charges in September.