Christian Hargrave-McKey, 30, was initially charged with murdering Mark Thomas, 60, who was repeatedly stabbed with his own knife at Bondi Junction on the evening of December 22 in 2018.

But Hargrave-McKey pleaded guilty in Sydney's Central Local Court on Tuesday to the less serious charge of manslaughter - a plea accepted by prosecutors on the basis of "extreme provocation".

While recovering in hospital from the life-threatening abdomen injury, he told police: "I am so disappointed in myself. I just found out what I did. I'm so sorry. That poor bloke".

Hargrave-McKey and a friend had shared a six-pack of beer before going to a Bondi Junction hotel, coincidentally arriving about the same time as Mr Thomas, according to the agreed facts.

The two friends, who were seen chatting to Mr Thomas at one stage, agreed to leave when asked by the manager who believed they were intoxicated.

After they bought takeaway food in Oxford Street, Mr Thomas walked past them and "spoke briefly" before putting his bag on the ground.

The three men pushed, shoved and shouted at each other before a woman tried to separate Mr Thomas and Hargrave-McKey.

The older man was observed to be muttering when Hargrave-McKey told the woman: "The man is trying to kill you" and pushed her out of the way.

Mr Thomas pulled open his backpack and took out a black-handled knife with a 20-centimetre blade from its packaging.

He stabbed Hargrave-McKey once between the chest and the belly, causing a deep wound which later required the removal of his gall bladder during surgery.

"The deceased left the knife in the offender," the facts state.

"The offender then removed the knife from himself and stabbed the deceased with the same knife 11 times to his back and chest."

Mr Thomas died at the scene, while Hargrave-McKey was found lying on his back in a garden bed.

Given the nature of his injury, social workers discussed end-of-life options with Hargrave-McKey at the hospital.

He told police he couldn't believe what had happened.

"I remember him with the knife and I said 'Go on, f***ing stab me then''."

Hargrave-McKey has been in custody since his discharge from hospital on January 3.

The case was adjourned to the District Court on November 8.

Australian Associated Press