Police are maintaining a high profile in central Christchurch, after fighting that saw three people admitted to hospital with injuries - one in serious condition.
They were called to the scene in St Asaph St, about 2.30am Sunday, and have established a cordon around the area, between Machester St and Colombo St.
Several brawlers were arrested and investigations are continuing.
Christchurch Police want to hear from anyone who may have been in the city last night and know anything that may assist enquiries.
Call them on (03) 363 7400 or through Crimestoppers on 0800 555 111.