A man was left bleeding on the ground after being assaulted with a hammer early Sunday morning.
Police were called to the chaotic street scene at the Hastings Clock Tower at about 1am after a group of people were fighting.
Senior Sergeant Dan Foley, of police Eastern District Command Centre, said police believed there had been an attack with a hammer which left one person in the group injured.
A police spokeswoman said witnesses reported that the man on the ground had head injuries and received first aid treatment at the scene.
Witnesses then chased one man who was involved in the fight towards Bunnings car park but he was unable to be caught.
However Mr Foley said one person had been arrested for alleged serious assault late yesterday morning.
The arrest was made after an alleged offender was spotted by a member of the public and possible assault witness in Heretaunga St East.
Police rushed to the scene and questioned a group of youths, as a member of the public stepped forward alleging at least one had been involved in the incident overnight.
In Heretaunga St yesterday police were talking to one youth when another person stepped forward pointing at another youth and saying: "That's him."
But Mr Foley told Hawke's Bay Today there was "a lot of work to do" on the inquiry, after a busy night typical of the first warmer weekend of each summer, with pre-Christmas and end-of-year revelry, including students returning home from university.
Police had attended many incidents of social and domestic order and Mr Foley said: "There's a lot of it at this time of the year."
Mr Foley said the police workload on the night meant there were still people to be interviewed.
Detective Glen Baker of the Hastings CIB said during the day police had no other information to release relating to the overnight incident while awaiting further statements.