Rape Crisis says a number of its centres and its overseeing body will shut their doors within the year if funding does not become more sustainable.
The organisation's government funding has been cut and most centres have had to reduce services or close altogether.
The Ministry of Social Development funds 25% of most of the centres' operating costs, with the rest coming from donations and contestable funds for which Rape Crisis must compete with the likes of sports clubs to secure.
Natalie Gousmett, from Wellington Rape Crisis, says figures from the Treasury show that sexual attacks cost the economy $1.2 billion a year, and this type of attack is the most expensive crime per incident.
She says volunteer counsellors help rape survivors to get their lives back on track and such a valuable service should not have to compete with sports clubs for money.
"We know that the support that we provide reduces the cost of that crime, because it enables people to go back to work, or go back to study, or continue parenting or continue being full contributing members of their society.
"And competing with other organisations - especially the likes of sports clubs - just doesn't make any sense at all."
The organisation's national co-ordinator, Georgia Knoll, says funding of the national collective used to allow for an office and three fulltime paid staff.
"Currently there's me and my funding's really temporary, so it should run out in the next year - which makes it really, really hard for us to plan on a national level for things to come when I'm simultaneously trying to plan for winding up."