The teenage birthday celebrant also received cuts to his neck after being struck by a bottle, witnesses said.
Police armed with semi-automatic rifles patrolled the street last night and Inspector Peter Raynes said two people were in hospital.
A witness, who declined to be named, saw a large pool of blood where the injured woman had been lying in the street.
An Auckland City Hospital duty manager said two people were in a stable condition last night.
The attack comes after a murderous start to the year, with knife attacks much higher than last year.
Figures show there have been 19 homicides in New Zealand this year. Last year there were 14 between January 1 and March 31.
Of the 19 homicides this year, eight involved knife attacks. There were 14 stabbing murders in 2011.
The spate has shocked one mother, Lynda Timmer-Arends, whose 27-year-old son Michael Valentine was found dead on a gravel road off State Highway One, just north of Levin, on February 1.
"It's horrific," she said. "We are hearing about too many young people who are carrying knives."
Stoyan Militch, 31, a chef, has been charged with Valentine's murder and assault with a weapon, a sharpening steel.
Two other men - Levin factory hand Michael Paul Zimmerman, 29, and labourer Brayden Windley, 22 - are facing charges of assault with a weapon. Police confirmed this week a joint murder charge had also been laid against those two.
They will reappear in court on March 27.
Changes to the Crimes Act a year ago increased the maximum penalty for possessing an offensive weapon from two years to three, and limited the ability of accused people to claim they were defending their property.
Valentine's stepfather, John, said the harsher penalties did not go far enough.
"What use are harsher penalties if judges don't use them? Judges need to be held accountable."
Police national crime services manager Detective Superintendent Rod Drew said it was not uncommon for homicide statistics to vary from month to month.
"We are concerned at the number of homicides so far but we expect these numbers to even out throughout the year," he said.
Justice Minister Judith Collins said the Government had taken action. "We have increased the maximum penalty for possession of an offensive weapon and introduced improved education about the dangers of carrying knives."
