"We are chronically underfunded.
"Every year it's a challenge to keep our service open and without any consistency and sustainable funding there's so much uncertainty. It's very hard to sustain a service like this."
Ms Gousmett said the agency was facing extra costs after demand for victim support services almost doubled last year.
She put the added demand down to the agency fronting a national campaign urging rape victims to seek help.
A shift away from their old building, which was down a "dark alleyway" and in need of earthquake strengthening, to a safer headquarters in the central city had also added rental costs, Ms Gousmett said.
The agency has launched a fundraising effort to raise the $55,000 it needs before next April in order to break even for the financial year.
It had gained about $3000 in 24 hours.
"It's great to see that support," Ms Gousmett said.
"We provide extremely effective and efficient services that benefit the whole community. It would be a tragedy if that service were no longer available to people in the Wellington region."
Neil, a father of a young woman who was raped, said cuts to services could be harmful to rape survivors and their families.
"I was concerned about my daughter and felt I had nowhere else to go. Without the support and practical, appropriate guidance I received at Rape Crisis I would have been struggling personally".
The client list at Wellington Rape Crisis grew from 543 in 2010/11 to 995 in 2011/12.
Long term client numbers increased from 140 to 179 in the same period.
The agency has been providing support services to rape victims for 35 years.
- Herald Online