The NSW Supreme Court on Wednesday heard the call Shahab Ahmed made to triple zero about 10 minutes after stabbing Khondkar Fariha Elahi to death in their Parramatta unit in February 2017.

In it, the operator answers, confirms his address and then asks "what happened?"

"I killed my wife," he said.

Asked if his wife of five years - lying on a blood-soaked mattress in the couple's bedroom - needed an ambulance, Ahmed said no.

"I've killed her ... with a knife ... just a couple of minutes ago," he said.

"I think she's dead."

The Bangladeshi-born Australian permanent resident has pleaded not guilty to murder, claiming the partial defence of substantial impairment by abnormality of mind.

Prosecutors rejected a guilty plea to manslaughter.

Police who arrived at the unit on the day of the stabbing found Ahmed with blood on the front of his tracksuit pants and were told he wasn't sure how many times he'd stabbed her.

"She was breathing for some time, then I called you guys," Ahmed told police, before admitting he hadn't checked on her between the stabbing and calling triple zero.

The prosecution and defence both agree the stabbing came immediately after the couple argued about Ms Ehali's secret affair with friend Omar Khan.

Ahmed snatched his wife's phone, demanded access to read her phone messages and threatened to kill her while holding a kitchen knife.

"I will show that you are lying. After proving that I will go away," he said.

After being granted access and seeing her ongoing contact with Mr Khan - including messages of a sexual nature - Ahmed began stabbing Ms Elahi repeatedly.

He smoked some cigarettes before calling triple zero.

Prosecutors allege Ahmed turned his mind to murder in 2016, when searching the web for "how should cheating be treated" and other terms.

"What is the punishment when wife cheat with husband", "what's the best punishment for married man caught cheating on their wives" and "marriage advice" (sic) were among other queries he made in December 2016.

Under cross-examination, the police officer who compiled the report into Ahmed's internet history said it was possible the accused had spent only seconds on the pages and there was no way to tell how much content on each page was read.

Ahmed's barrister has argued his client was substantially impaired by a depressive illness at the time of Ms Elahi's death.

The agreed facts state a general practitioner referred Ahmed to a mental health treatment plan in 2015 while Ms Elahi called police in September 2016 after she believed he would harm or kill himself.

The judge-alone trial before Justice Monika Schmidt will resume on Tuesday.

Australian Associated Press