Baby Cezar's mum a liar - defence

Cezar Taylor. Photo / supplied

The mother whose baby was violently shaken and killed has been "grinding her axe" at the High Court at Auckland, the jury was told today.

James Hemana is on trial for the murder of six-month-old Cezar Taylor, his partner's baby.

He has pleaded not guilty but has admitted failing to provide the necessaries of life.

The Crown says Hemana murdered baby Cezar out of anger and jealousy when he violently shook Cezar and dropped him on to his bed head-first. The child's head also collided with a cabinet.

The mother of baby Cezar, Victoria Taylor, gave evidence at the trial and told the court that there were two shaking episodes and an occasion when Hemana slapped the baby in the back of the head, causing Cezar's head to come forward and collide with his walker.

In his closing, defence lawyer Steve Bonnar said Ms Taylor was a "demonstrated liar" who had lied to police, her family and medical staff who were trying to save the life of Cezar.

"Unfortunately, ladies and gentlemen, Ms Taylor has a very big axe to grind and she's been grinding away at it for three to four days in this court case."

Mr Bonnar said much of the evidence given at trial about his client was "prejudicial" and that the jury should focus on what his client was thinking on July 13 when the fatal shaking incident happened.

Mr Bonnar also questioned the Crown's explanation of what Hemana was thinking at the time.

"This is a court of law. This is not amateur psychology hour."

He said his client accepted that he caused the death of Cezar and had pleaded guilty to manslaughter.

"He is the only person in the whole sorry saga who has accepted any responsibility at all. Ms Taylor doesn't accept any responsibility for her own failure to obtain medical assistance and the Crown don't seek to sheet that responsibility home to her.

"They've granted her immunity from prosecution."

He said the jury had to focus on the July 13 shaking episode which lasted only seconds.

"You need to focus on that real issue, what was going on in Mr Hemana's mind, really in the five to six seconds when he shook and dropped Cezar."

He said the jury would need to find Hemana had murderous intent, and knew at the time that what he was doing was likely to cause the death of Cezar.

The trial continues.