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.
Wiszniewski said the Criminal Investigation Branch is looking into what happened but no charges have been laid yet.
He said there's no information that suggests the incident was gang-related.
Local resident Kathleen Burns said the party woke her up at 3am. She looked out the window and saw three cop cars and lots of people. She said the party looked close to Naenae Primary School.
"I heard lots of voices and yelling.
"But I didn't hear screaming or anything to make me really alarmed."
She said the street is really long and one end is known to be troublesome. Burns said she's heard of lots of burglaries and you frequently hear drunk guys walking down the street. But they don't often get many parties she said.
One man who lives on the street said the party started out as a happy and friendly affair, but became raucous. He saw a large police presence and police dogs.
Later on when police arrived he said he heard screaming.
A Waddington Drive resident who doesn't want to be named said that she had been robbed five times and her neighbour had been robbed four times since they had lived there. She said the street gets lots of traffic.
"It's a bloody race track for cars, because it's a straight road.
"The cars just roar up here."