A Sydney man who was stabbed in the abdomen pulled the knife out of his body and used it to kill his attacker, a court has been told.

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 last year.

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".

He suffered a life-threatening injury after Mr Thomas produced a knife with a 20-centimetre blade from his backpack and stabbed him in the abdomen after they'd pushed, shoved and shouted at each other outside a fast food shop.

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