A central Christchurch street is cordoned off after a brawl left three people in hospital, one with serious injuries.

Christchurch police were called to reports of fighting on St Asaph St before 2.30am.

Three people have been admitted to Christchurch Hospital after the brawl which left one person in a serious condition. Two others suffered moderate injuries.

Police say a number of people were arrested at the scene - near the intersection with Manchester St - for fighting.

A section of St Asaph St remained under a police cordon.

Diversions were now in place and traffic was unable to travel west on St Asaph St between Manchester St and Colombo St.

Police said the public could expect to see a continued police presence in the area today as investigations focused on who was behind the attack on the three men now being treated in hospital.

Police are appealing for anyone who was in the area who may have information that could help to contact them on (03) 363 7400 or anonymously on 0800 555 11.