Support groups like Women's Refuge are concerned they'll be made to give up the names of their clients in return for funding.
The Ministry of Social Development wants the groups to share the names to ensure funding gets to the right people.
Mother-of-two Leigh Friday sought help from the Wellington Women's Refuge after years of abuse by her ex-partner.
When all her family and friends were in her home country of South Africa, she says the agency gave her the courage to walk away from abuse.
"It was just knowing that it was going to be okay ... it wasn't something unusual that I had failed at," Ms Friday told Newshub.
She says she wouldn't have gone to Women's Refuge if her details were being passed on.
"When you're in a vulnerable place you want to know you're going somewhere that you're going to be safe."
In June, social service providers like Women's Refuge will be required to hand over the names and addresses of their clients to receive funding.
Those who help sexual abuse victims are exempt from this for 12 months, but other groups say their clients are just as vulnerable.
At parliament on Thursday, they voiced concerns that vulnerable people will be worried about their details falling into the wrong hands and that could stop them seeking help
Manager of Wellington Women's Refuge Philippa McAtee says the data-for-funding move is of such concern they will seriously consider looking elsewhere for funding.
"I believe this is a matter of keeping people safe and it puts lives at risk."
But Social Development Minister Anne Tolley says that information will be secure and that it is vital to ensure funding is going to the right place.
"We spend $330 million in taxpayers' money every year, we've got the anonymised data, that doesn't tell us that the right people are getting the right services," she says.
The Privacy Commission is investigating the changes and is expected to report back by the end of the month.