A High Court jury has been told it will have to decide if an Indian immigrant charged with murdering his wife "lost it" when he killed her three years ago.
Laxman Rajamani, a 36-year-old accountant, is on trial in Auckland for a second time accused of murdering Chitralekha Ramakrishnan at their home in suburban Auckland on January 13, 2005.
Rajamani was found guilty by a High Court jury in 2006 but the Supreme Court last year quashed the conviction and ordered a retrial.
His lawyer Paul Dacre said Rajamani admitted it was he who slit his wife's throat at their Mt Eden home, and he took responsibility for his actions.
But he said Rajamani was provoked into losing his self-control by the words or actions of Ms Ramakrishnan.
"Put simply, his defence is that he lost the plot," Mr Dacre told the jury of eight men and four women.
The provocation defence required Rajamani to prove his wife's actions or words were sufficient to deprive the ordinary person of the power of self-control.
If the jury finds the defence of provocation is applicable, Rajamani would be guilty of manslaughter and not murder.
But crown prosecutor Alysha McClintock said the crown would argue the evidence would show that Rajamani's actions clearly met the threshold of murder and that the provocation defence did not apply.
She told the jury the pair were married following a traditional arranged Hindu marriage in India before coming out to New Zealand and taking up good positions in the finance industry.
Ms McClintock said evidence would be called that the pair had a rocky relationship, and that this coupled with Rajamani's unhappiness at work caused him some stress.
Eventually Ms Ramakrishnan had an affair with a Pakistani man, and she asked a friend to tell Rajamani their relationship was over.
Not long afterwards, Rajamani bashed his wife over the head with a brick before slashing her throat in the kitchen, Ms McClintock told the jury.
She said Rajamani then made an ineffective attempt to clean the scene up and threw the brick out the window. Later that day he also bought 70 litres of petrol and considered setting fire to the home.
Rajamani also tried to book a flight back to India but he also talked to his family and they persuaded him to give himself up.
When police visited his home after he called them to say he'd killed his wife, he asked "what is the penalty for murder in New Zealand", she said.
Ms McClintock said it could not be argued that the news Ms Ramakrishnan wanted to end the relationship counted as provocation under the law.
"That happens every day of the week in this country," Ms McClintock said.
"But it wouldn't deprive the ordinary person of the power of self-control. Most marriage break-ups do not result in one spouse killing the other."
Justice Judith Potter told jurors that the fact they were hearing a retrial was irrelevant and they could only judge Rajamani's guilt on the evidence before them.
The trial is expected to last two weeks.