A rape prevention group says funding cuts are frustrating police and advocates for victims of sexual violence.
More than $6 million of funding for such services has been cut, following recent changes by the ACC.
The HELP Foundation, which offers a 24-hour helpline, has also lost $200,000 in funding.
The director of Auckland Rape Prevention Education, Kim McGregor, says the service cuts are affecting the ability of police to prosecute sexual offenders, by denying support to victims.
Ms McGregor says lack of support for sexual assault victims can cause a court case to stall or fail, potentially costing the taxpayer millions of dollars.
She says there is a lack of support across the board, with Maori sexual assault services now down to just two providers nationwide.