Samuel Pou was drinking beer with a friend when he allegedly confessed to killing his partner Bridget Simmonds and burning her body on a farm in Northland.
The chilling evidence was given in the High Court at Whangārei on Friday by David Erihe who said Pou told him that he "wasted her, got rid of her" but didn't elaborate how.
Pou, he said, wasn't a close friend of his but he knew Pou's younger brother.
Samuel Pou is accused of killing Simmonds, who he was in a relationship with, between February 23, 2019 and March 16, 2019, and burying her body in a shallow grave on a property on Wilson Rd in Parakao.
The Crown case is he punched Simmonds more than 100 times for over an hour after she spilled wine in a hut the couple were living in, which led to her death.
His nephew Te Koha Samuel Pou is also on trial on charges of dishonestly using Simmonds' bank card and helping his uncle avoid arrest.
Erihe told the jury he had met Simmonds on a couple of occasions only, including once when she came to his house with Samuel Pou.
When he was drinking beer at his Otangarei home one evening with Samuel Pou, he said the latter told him: "Remember that chick I brought over. I knocked her off, I wasted her and tried to burn her in a fire to get rid of her."
Erihe said he did not feel comfortable hearing all that and advised Samuel Pou to hand himself in.
However, he said Samuel Pou was "blase" about his advice, allegedly claiming to have killed her because of charges relating to an assault.
He wasn't aware of the assault charges against Samuel Pou until that stage, Erihe said.
Samuel Pou stayed with him for a couple of months after that drinking session, Erihe said.
He said he had been drinking beer for two hours before Samuel Pou arrived.
Taxi driver Rajvinder Jawandha, who picked up Simmonds on February 23, 2019, from Countdown Regent where her mother had dropped her off, also took the witness stand.
He said Simmonds was carrying shopping bags and a "big bag" which he helped put in the taxi before he headed to the house she was living in on Wilson Rd.
When he dropped her off, Jawandha said he could "feel" someone was inside the house but didn't see anyone.
The three-week trial before Justice Christine Gordon resumes on Monday.
Simmonds body was excavated about 15 months after she was reported missing.