Changes to benefit payments have made it easier for abusive partners to withhold money, according to a charity.
Welsh Women's Aid said universal credit, which combines multiple benefit payments into one, was "enabling" financial abuse.
One woman from south Wales claims she was "dragged" to the bank and forced to take out a loan by her former husband.
The Department for Work and Pensions said its staff were trained to support victims of abuse.
Universal credit merges a string of previously separate benefits into one payment - now paid into one bank account.
The charity said abusive partners manipulate the system by getting universal credit paid into their account and keeping it for themselves.
One woman from south Wales, who does not want to be identified, said her former husband brandished weapons and "took the reins" of her finances - building up debts in her name.
"He ended up dragging me down to the bank to get a loan out in my name that he had already investigated," she said.
"[My husband] popped out of the room to get a leaflet, I was able to signal to the bank manager that I did not want to be there.
"He said 'I can see that' but, in the end when the forms came through, he stood over me and I signed them," she added.
Welsh Women's Aid said 38% of women accessing specialist violence services in Wales in 2016-17 were identified as victims of financial abuse.
It said welfare reforms such as the benefits cap and changes to housing benefit were making it more difficult for people to leave abusive relationships.
By 2022, more than 400,000 households in Wales will receive universal credit.
Gwendolyn Sterk, public affairs manager at Welsh Women's Aid, said the new single payment system needed to change.
"We need a system that recognises a women's right to an independent income, rather than going back to the idea that one bread-winner would have that money paid into their account - and give them ultimate control over the whole finances of that household," she said.
While claimants in abusive relationships can arrange split payments, many were reluctant to do so out of fear the abuse would get worse, the charity said.
A DWP spokesperson said: "Domestic abuse in any form is completely unacceptable and we are committed to doing all we can to improve support for people affected.
"Our staff are trained to support vulnerable people, including those who are victims of domestic abuse.
"That includes referring people to specialist organisations for more support and alternative payment arrangements can be made for those on universal credit."
- The Wales Live Fear Free helpline provides 24-hour, confidential help and support to adults and children in Wales who have experienced domestic abuse, sexual violence or any other form of violence against women. Contact the Live Fear Free Helpline on 0808 80 10 800.