Four men have been treated for stab wounds following an apparent gang fight on the streets of Timaru.
Police say they received multiple calls around 3:20am on Friday, residents on Dunkirk St reporting "a number of gang members fighting".
Three were initially rushed to hospital - two in a moderate condition, and have since been discharged, and the third in a serious condition.
The fourth man arrived shortly afterwards, and is surgery.
" We'd like to speak with anyone who saw or heard anything in this area in the early hours of this morning who hasn't yet spoken to police," said Det Sgt Greg Harrison.
Police believe those involved in the fight are known to each other.