The man stabbed in an attack at Orewa, north of Auckland, on the weekend will lose the use of one of his eyes.
The 26-year-old suffered a dozen stab wounds in the early morning attack on the beach on Saturday. He had earlier been seen arguing with two people in the recreation area on the main road through town.
Police want to talk to a young couple who were in the area at the time of the stabbing.
They are a Maori or olive-skinned Caucasian man with long dreadlocks, who was wearing only jeans and aged between 25 and 35. With him was a young Caucasian woman aged about 23. She is about 1.62 metres with long black hair and was wearing a black top and possibly a summer dress.