A paediatrician has dismissed claims the one-year-old brother of the Kahui twins caused their fatal injuries.
Crown prosecutors allege Chris and Cru Kahui's father Chris fatally injured the twins while at home on June 12, 2006.
The twins were taken to Middlemore Hospital the next day and transferred to Auckland's Starship Hospital where they died on June 18, about 14 hours apart.
Kahui has pleaded not guilty in the High Court at Auckland to their murder. Defence lawyers say someone else, probably the twins mother Macsyna King, caused the injuries.
The trial, in its second week, resumed today after being forced to take a recess yesterday due to the junior doctors' strike.
Crown prosecutors had to reschedule the medical experts today because many of them had to cover for their junior counterparts.
When the twins were first assessed by their family doctor and then questioned by hospital staff, both parents said their one-year-old toddler Shane had climbed into their cot and banged their heads together.
Dr Alan Drage, a consultant pediatrician at Kids First children's hospital, said the injuries could not have been caused by the toddler.
"Taking into account Shane's age, size, strength and developmental status, I am quite certain that Shane could not have inflicted the injuries sustained by his younger brothers," Dr Drage's statement, read to the court, said.
Dr Wendy Clark, clinical director at Kids First children's hospital, gave evidence today Ms King seemed "wary and defensive" when told the Kahui twins had brain damage and that hospital staff had called police.
Dr Clark said CT scans revealed the twins' conditions were the result of injuries and not some medical issue.
She told Ms King this and asked how this could have occurred.
"She said their older child had pulled them against the bars of the cot," Dr Walker said.
She said police being called in these sorts of circumstances was not uncommon and Ms King was told this, the New Zealand Herald reported.
Crown prosecutor Simon Mount asked the doctor what Ms King's behavioural and emotional response was when told of the dire situation the babies were in.
"She became upset. I think she started crying at that stage....She asked for cultural support and patient advocate (and) seemed wary and defensive."
Later, it was decided the babies needed to be taken to Starship Hospital in Auckland.
Dr Carl Horsley said Ms King refused to travel to Starship Hospital with the critically ill babies even when told that they could die on the way.
The court also heard how Ms King left the intensive care unit with one of her sons even though he was drawing his last breath.
She picked baby Cru from his tiny hospital bed and went to walk outside because she thought he needed fresh air.
Dr Fiona Miles said she was told by a nurse that Ms King had taken Cru and was heading outside. Dr Miles "raced" to stop her and meet her at the doors.
"I intercepted her and asked what she was doing... she told me she wanted to take him outside for some fresh air."
Dr Miles said it was inappropriate and asked her to stop but was told she was not "being compassionate and didn't understand."
To defuse the "unusual and tense" situation Dr Miles agreed they could walk a few steps and then turn around and return to intensive care.
Dr Shuan Dai, an eye specialist, said the autopsy performed on the twins on June 14 showed severe haemorrhaging in their eyes caused by shaking and impact.
Cru had the worse haemorrhaging of the two, he said.
The freshness of the damage indicated it was caused anywhere between 72 to 48 hours before the autopsy, suggesting either June 11 or 12, he said.
The trial resumes on Monday.
