A man is in a critical condition after being stabbed at a 21st birthday party in Lower Hutt.
Emergency services were called to a house in Naenae around 2.30am after reports of a disturbance at a party on Waddington Drive.
A man in his 20s was taken to Wellington Hospital with six stab wounds.
Police were called to a report of fighting in the street, possibly involving 50 people.
Police said emergency service workers were put in unnecessary danger when an ambulance was pelted with bottles.
Central police shift commander Paul Wiszniewski said one man has been arrested for assault and is likely to appear in court today.
A further eight arrests were made for disorder and obstruction type offences.