A rape prevention group fears a nationwide increase in sexual violence during the Rugby World Cup will overwhelm support services.
Kim McGregor, director of Rape Prevention Education, said a combination of thousands of overseas visitors and excess drinking during the cup would inevitably lead to more sexual attacks on women and men.
She expected an influx of victims seeking support and counselling during and after the cup celebrations.
"It's extremely worrying and extremely frustrating. We're concerned for the women. The young women in particular. There will be rapes and sexual assaults in the Auckland area and throughout the country.
"Our frontline services will do their very best for the survivors and their families but I can't imagine that they're going to cope."
Dr McGregor said a 2010 decision to cap ACC-funded counselling at 16 hours for victims of sexual violence without a diagnosed mental injury put her organisation under severe strain.
Many staff had found other jobs and it would be difficult to rehire them for the rugby tournament.
Dr McGregor said more planning and resources were needed to stop rapes and other attacks in wide-open areas such as fan zones.
"We've had years to prepare in time for the Rugby World Cup. We know there will be an increase in sexual assaults during that time. But we have had no increase in funding.
"These young women or men will have to find their own way to the police station."
Emma Castle, manager of the Counselling Services Centre in South Auckland, said her staff were bracing for a "massive increase" in work due to the Rugby World Cup.
The Centre, which provides a 24/7 callout service for sexual assault victims, had already seen a 66 per cent increase in its workload since 2007, she said.
She claimed its funding had not increased since it started providing the callout service in 1995.
However, police spokesman Jon Neilson said statistics did not show an increase in sexual violence after rugby test matches in New Zealand, and that was not expected to change during the Rugby World Cup.
"All our research supports this, based on the evidence in our records from past years. There can be a very small rise in street disorder on occasions, but not always, in the city in which the match is played."
Visitors arriving for the Rugby World Cup would be issued a pamphlet on keeping themselves safe, Mr Neilson said, and officers would be patrolling fan zones and making sure that liquor bans were enforced.