Warning: The Grace Millane murder trial is hearing evidence of a graphic and sexual nature. Reader discretion is advised. The trial is taking place in open court and media are required to accurately report the evidence as it is presented.

The man accused of Grace Millane's murder won't take the stand and give evidence in his own defence but friends of the British backpacker have.

The case, which is being heard in the High Court at Auckland, is now in its third week.

Crown prosecutors allege that on the night of December 1 last year - the eve of Millane's 22nd birthday - the accused strangled Millane to death in his CityLife hotel apartment in downtown Auckland.

The accused's lawyer, Ian Brookie, told the court this morning: "The defendant elects not to give evidence but as may be apparent now he elects to call evidence."

Alcohol likely played a role in Millane's death - expert

3.15pm

Crown Solicitor Brian Dickey cross-examined pathologist Dr Fintan Garavan this afternoon.

Garavan told the court the "major participant" in Millane's death was pressure on her neck - corresponding with the Crown's expert pathologist Dr Simon Stables.

A lack of defensive wounds or signs of struggle, Garavan accepted, could be because the victim was unconcious and not in a position to defend themselves.

Garavan said manual erotic asphyxiation was "not common" but he was aware of other cases.

Dickey asked if sex, particulary which might be described as "acrobatic", might be difficult for people when drunk.

The doctor, however, said sex wasn't a complicated activity. He added it was quite easy to perform while intoxicated, unlike flying a commercial jet.

But Garavan said he couldn't comment on who drank what or how much based on the orders of drinks bought by the accused and Millane on the night they met.

He, however, disagreed with Stables' position that alcohol would not be a factor in Millane's death.

"I have a PHD in toxicology, he doesn't. But that's okay," Garavan said.

2.40pm

Pathologist Dr Fintan Garavan continued giving evidence this afternoon and said the practise of erotic asphyxiation was "actually well-known and has been described for many hundreds of years".

However, he continued, it was far more common for people to practise solo auto-erotic asphyxiation.

The doctor said the narrative of rough sex from the accused was "an adequate" explanation as to how Millane may have died.

The absence of injuries to the deeper structures of Millane's neck - and no evidence of resistance - also added further gravity to the accused's claim.

Alcohol may have also meant the "safety valve did not kick in", Garavan said.

2.15pm

Dr Garavan gave evidence via video link from Miami in the United States this afternoon.

He is forensic pathologist and expert in the effect of drugs and alcohol on the body.

Brookie first asked the doctor about the bruising found on Millane's body.

"It's a bruise, [but] it doesn't tell me what caused it necessarily," Garavan commented on a bruise on Millane's neck.

He also said there were no signs of any defensive injuries on Millane's body.

"The fingernails are not particularly helpful," he said.

Garavan further explained - as had been evident in fatal hanging cases - that a "sharp force applied around the neck" in the right place can "stop the heart very quickly".

Millane's alcohol intake, he continued, could "very well have been a secondary factor in the cause of death".

The backpacker had several drinks on the night she died, including shots of tequila and cocktails, which Garavan said was "a significant amount of alcohol to ingest over a short amount of time".

He likened Millane's alcohol consumption as an "iceberg that's making its way for the shipping lane".

He said it was "very likely [it] has became a very important indirect layer in causing death".

Friend of Millane gives evidence for defence

12.25pm

A friend of Millane, whose identity is suppressed, had her statement read to the court.

She said Millane had "a type" in a man.

"Grace liked the rugby player type of look. Grace's taste rarely went away from that type."

Part of "girl talk", she said, included discussing their sexual preferences.

Millane "enjoyed her partner putting her hands around her neck", BDSM and rough sex, she said.

She also mentioned Millane would use handcuffs on occasions.

A statement from a man who knew Millane was also read to the court but the details are unable to be reported due to an interim suppression order.

The court also heard evidence that Millane held accounts on Whiplr and FetLife, online BDSM and sexual fetish communities.

She last accessed her Whiplr account on December 1 last year - the day she met the accused - from her backpackers in Auckland.

'No motive' - defence opens its case

10.55am

Defence lawyer Ron Mansfield continued his opening address and told the jury the Crown's prosecutors had shown no evidence of "some assault, for which we have absolutely no motive for".

He said the accused and Millane were an "otherwise happy couple, having fun, and consensual sex" on the night of December 1.

CCTV footage of the pair shows them drinking, laughing and kissing throughout the evening.

The accused claims Millane died during rough consensual sex, where she had asked him to choke and hold her neck.

There was no anger or violence, Mansfield said.

"There is an absence of any motive.

"None of the people who were occupying the room right next door heard any disturbance."

What the accused did after Millane died "doesn't stand him in good stead", Mansfield said.

"People do things when they're stressed, when they're panicked," he added. "The opportunity for him to do the right thing was relatively narrow."

The lawyer said his client "panicked out of a fear of the consequence" when he disposed of Millane's body and evidence.

"Because who was going to believe him that death occurred during a consensual sexual activity?

"Nothing you do from that point on is going to look good.

"As reprehensible as you might find some of his conduct, you might find it tells you very little about when Ms Millane died."

Mansfield said the sexual interests of Millane would be discussed as part of the defence as the accused's had during the Crown case.

"I want to be very clear that no one is trying to shame Ms Millane or her family and no one is trying to blame Ms Millane and her family. And I'm certainly not suggesting that she's not normal."

Millane was a "loving, bright, engaging, intelligent and well-liked woman", Mansfield said.

"That is her reputation and that should be her reputation and memory at the start of this trial and at the conclusion of it."

The defence case will include evidence collected by the New Zealand Police and a private investigator hired by the accused's legal team, Mansfield said.

10.35am

Mansfield gave the jury an opening statement today where he talked about "blame and shame".

"Blame and shame are two concepts we learn about very early on in our childhood … it's ingrained within our society and community," he said.

Mansfield told the jury it was used as weapons by the extreme religious, political and moral conservatives in our society "to keep us within their definition of normal".

"I say their definition, because normal is a very subjective term. What is normal?"

But, he said, in the modern Western world people are more prepared to discuss things openly.

"People are far more prepared to not live within those religious, political or moral confines that were imposed on older generation such as mine or perhaps yours."

He said this extended to people's consensual sexual lives.

"The justice system does involve concepts of blame and shame," Mansfield said. "The justice system is not interested in the political, religious, social, moral normal ... It's interested in the law - lawful conduct or unlawful conduct.

"When it comes to a courtroom we are interested in whether someone has committed criminal wrong. Simply stripped away, whether their conduct is unlawful … whether it's a crime."

Mansfield said: "In this trial, if we're not careful, our own religious, political, social or moral views can distract you."

The well-known lawyer said he was interested in the concept of normal.

"I suppose in this trial whether sex was normal or kinky?

"When it comes to sexuality or sex, don't we all now accept that there is no normal? That, within the confines of consent, people should be free to be who they are ... and be intimate with each other as they chose to be intimate with each other."

Mansfield said whether the jury or others condoned certain sexual practices was irrelevant.

The accused, Mansfield continued, was "playing out his life through Tinder" where he would misrepresent his position or career which he had a tendency to continue after he met women.

"He was so insecure as to think that portraying himself in that way that women were more likely to meet up with him and engage in a relationship," Mansfield said.

He told the court this could be a "reflection of the Instagram age" where people present themselves in the best possible way even if it is a fabrication.

"In this trial, like it or not, we have no choice but to confront what happened in [the accused's] bedroom at the CityLife that night. Because that is where we know Ms Millane died. And we are here to investigate how Ms Millane died."