Warning: graphic content

The victim of a home invasion was found deceased gagged and hog-tied on his bed and would have suffered "in unimaginable pain from his injuries", the High Court was told today.

Don Ekeroma, 35, and Benny Fatu, 29, have pleaded guilty to aggravated robbery but deny murdering Shannon Baker on December 11, 2018.

The opening arguments of their shared jury trial in High Court at Auckland before Justice Pheroze Jagose have been heard this morning.

Shannon Shelby Baker was found dead inside his Sandringham home on Calgary St.

Crown prosecutor Brett Tantrum said he was the victim of "a severe beating".

There were a number of bruises on Baker's body, his left eye was ruptured and his nose was broken.

The Crown would later provide evidence from a medical expert that he would have been "in unimaginable pain from his injuries".

He was restrained in a way that it was "unlikely he could move easily, perhaps impossible".

His arms were tied together behind his back, his feet were tied and they were then tied to his hands - a more common description of this is often the word "hogtied", Tantrum said.

His cause of death was asphyxiation but strangulation could not be ruled out, he said.

One of his friends made the grisly discovery.

Walking through an open door the friend found things strewn about the apartment.

When he found Baker and removed a gag "it was obvious" he had died.

At 7.05am the friend rang 111 with officers arriving on the scene 20 minutes later.

Police outside a block of units on Calgary Road, Sandringham, where Shannon Shelby Baker was found dead. Photo / Leon Menzies

Fatu's defence lawyer Graeme Newell said the evidence in the trial by in large would not be contested but the issue was what the jury could draw from the evidence.

"More importantly what can the Crown prove beyond reasonable doubt?"

"Was Mr Fatu even present in the flat when Mr Baker was gagged?

"There is no evidence at all that Mr Fatu intended that Mr Baker died."

The defence say whatever took place in the Sandringham flat that night "the death was inadvertent".

Ekeroma's lawyer Lester Cordwell queried whether his client meant to cause Baker serious harm and if he knew it would likely cause his death.

The defence states in the "strongest possible terms" that the answer to both of those questions is a "resounding no."

But his client was not trying to "side-step" responsibility here as he played a part in the death.

"He should be found accountable for the verdict of manslaughter."

Yesterday, Justice Jagose told the jury the "determination of the relevant facts" was completely up to them.

He urged the 12 jurors not to jump to conclusions and to try to not reach any conclusion until the trial is complete.

"Both Mr Ekeroma and Mr Fatu are entitled to have you approach the case with an entirely open mind."

It was for the Crown to prove its case beyond reasonable doubt, he said.

Anyone charged with a crime is "deemed innocent until proven guilty".

The trial is expected to last for two weeks.