Murder trial of Shane Claude Roberts continues in the Rotorua High Court

Karlos Stephens. Photo / File

The trial of murder accused Shane Claude Roberts has been further adjourned in the High Court at Rotorua.

The adjournment until tomorrow came an hour after Edinburgh-based neurological pathologist Professor Colin Smith began his testimony via audio-visual link.

Roberts, 60, pleaded not guilty to the murder of 10-month-old twin Karlos Stephens at Rotorua, some time between November 20 to 30, 2014.

Before the adjournment, Smith told the six-man six-woman jury his credentials included being a specialist in paediatric neuro trauma, which led to baby Karlos' case being referred to him.

It was his opinion the injuries he suffered, which were bleeding on both sides of his brain and behind his eyes,"very much" indicated he'd been subjected to external trauma.

Shane Claude Roberts is accused of the murder of baby Karlos Stephens. Photo / File

"I cannot say in this case whether there was shaking or impact but either could potentially cause this nature of trauma," he said.

The effects of both were immediate. Normally he would have expected to see external bruising but there had been none on baby Karlos' body.

Responding to a question from Crown solicitor Amanda Gordon, the professor said it would be immediately obvious to any competent caregiver an injury of the type Karlos received the infant would be "very, very poorly".

He would have been unresponsive and not engaging with people, he said.

"This was a level of force [applied] that adults do not accept as reasonable ... this is a level of force not accepted in society," Smith said.

He discounted the injuries Karlos received could have been caused by the child developing flu-like symptoms. When he had microscopically examined tissue from Karlos' brain it was clear he had died from lack of blood flow.

He had survived for a period of a few hours after his injury was inflicted but he was unable to say how many hours.

The trial, which is before Justice Matthew Muir, is set to resume at 10am tomorrow.