The Christchurch woman who stabbed her partner to death and buried his body in his compost heap has taken the stand to defend herself today at her murder trial.

She claims the fatal assault came after an "altercation" and the death was the result of "both" of their actions.

Rena Joyce is accused of murdering Berry, 55, at his Main North Rd home on or around December 29, 2020.

He was stabbed in the neck and back and his throat was cut.

The Crown alleged the attack only stopped when the blade of the knife Joyce was using lodged in Berry's spine and broke away from the handle.

Berry's body was then dragged from his home and buried in a compost heap, under rotting food, leaves and vegetation.

It is unclear whether he died in the house or while lying in the crude grave.

Berry's remains were found two weeks after he died - when Joyce went to the police and confessed she had "manslaughtered" him.

She says the death was accidental and has pleaded not guilty to a charge of murder.

This week the jury heard from 31 Crown witnesses.

Police at the scene of the alleged murder. Photo / Anna Leask

The Crown closed its case this morning and defence lawyer Richard Peters then opened the defence case, saying Joyce would give evidence.

He asked her to confirm that the information she gave to police at her evidential interview the day of her arrest were correct.

She said yes, they were.

Peters then handed over to Crown Prosecutor Pip Currie for cross-examination of Joyce.

Joyce confirmed her relationship with Berry was "dysfunctional" and there "was a good deal of violence".

But she rejected that she was the main aggressor of the domestic violence.

"No, (it was) both of us," she told the court.

"We both assaulted each other ... We were both dysfunctional at the time, and it was 50/50."

Joyce claimed she could not recall details of some assaults on Berry because she was "so intoxicated".

Initially, Joyce argued with Currie saying she "would not kill anyone" and did not accept she killed Berry - despite her two-hour confession to police.

"Accidentally, he was hurt ... I admitted to manslaughter and accidental without intention," she said.

"(It was an) altercation between two people ... It was a joint decision, there was a lot of alcoholism and drugs involved.

"It was both of us - we both got hurt."

Rena Joyce aka Moloney is on trial in the High Court at Christchurch for allegedly murdering her partner Martin Berry in 2021. Photo / Pool

She conceded she did kill Berry "to a certain extent".

"But it was not death intentional ... I would say it was a combination of everything but yes his death happened ... I have acknowledged that but it wasn't just me alone," she said.

She denied cleaning the crime scene.

She said she used sheets and a rug to cover it and cleaned the rest of the house but left the site where she killed Berry so police could "get DNA".

Currie put to Joyce that she had shown no remorse - even in her confession.

"You were feeling sorry for yourself and what a bad situation you had got yourself into," she said.

"You seem to be more concerned about what was going to happen to you."

Joyce agreed with Currie "to a certain extent" then reeled off that she was "very ill" when she handed herself in and had not eaten or slept for 10-14 days and there could have been "a bit of confusion" around her story.

"I loved Martin, I always loved Martin and I've always stood by him ... but I can't change him," she said.

Joyce explained why she did not try and get help for Berry after the stabbing - which Currie said was "callous" and undignified.

"He was dead ... He died in my arms, when we had the altercation he died," she said.

"I had a little bit of a blackout, when I came to, yes he was removed from the property ... I don't deny it."

Rena Joyce aka Moloney is charged with murdering her partner and dumping his body at his Christchurch property. Photo / Pool

She denied "dragging" Berry and said she "gently put him by the bird bath" by pulling his body on a sheepskin rug.

"You don't know what went on at that property, I know what went on and I'm here to tell you," Berry stated.

Currie also grilled Joyce on where Berry's possessions went after his death.

The jury heard earlier that the only items left in the house were his records, some shoes and books.

The Crown alleges Joyce dumped his property in a number of rubbish bins.

Joyce refuted that today saying while she gave some clothing to "the homeless" she had the rest with her.

She said as his partner she was "entitled to" Berry's belongings including "wedding bands, engagement ring and clothes".

"I have them at the prison ... I'm keeping them - this is somebody that I loved and cared about."

Currie accused Joyce of lying in her statement to the police and trying to "blacken" Berry's character.

"Towards the end of the relationship it was very toxic, we couldn't live with each other, we couldn't live without each other," Joyce replied.

She said on the night of the alleged murder she felt "a combination of anger, love, hate" towards Berry.

The trial continues.

FAMILY VIOLENCE - DO YOU NEED HELP?

If you're in danger now:

• Phone the police on 111 or ask neighbours of friends to ring for you.
• Run outside and head for where there are other people.
• Scream for help so that your neighbours can hear you.
• Take the children with you.
• Don't stop to get anything else.
• If you are being abused, remember it's not your fault. Violence is never okay

Where to go for help or more information:

• Shine, free national helpline 9am- 11pm every day - 0508 744 633 www.2shine.org.nz
• Women's Refuge: Free national crisis line operates 24/7 - 0800 refuge or 0800 733 843 www.womensrefuge.org.nz
• Shakti: Providing specialist cultural services for African, Asian and middle eastern women and their children. Crisis line 24/7 0800 742 584
• It's Not Ok: Information line 0800 456 450 www.areyouok.org.nz