Benefit system changes are failing families in Wales and pushing them into debt, Citizens Advice has claimed.
By 2022, more than 400,000 households in Wales will receive Universal Credit - a scheme which combines all benefits into one.
But Citizens Advice said it was already leaving people in pilot areas, like Flintshire, dependent on food banks.
The Department of Work and Pensions (DWP) said most claimants were "satisfied".
There are currently 22,000 people on Universal Credit in Wales, the UK government's troubled flagship welfare scheme, being rolled-out across Britain.
Introduced in 2013, its single payment replaces six benefits, including Jobseeker's Allowance (JSA) and Employment and Support Allowance (ESA).
Citizens Advice said the system was overly complicated and "already failing too many people", pushing them into debt and leaving them without the means to make ends meet.
A report highlights issues in Flintshire, Wrexham and Newport, where incorrect information and harsh sanctions are leading to payments being rejected or delayed for weeks.
The charity said the UK government should pause a planned acceleration of the roll-out programme to Job Centres until key issues are addressed.
Citizens Advice spoke to claimants including Amanda, from Newport, who said she has creditors calling at her house several times as day after her payments were stopped for eight weeks after she changed her claim when her partner moved in.
Harry, from Flintshire, said he was given incorrect information about which benefit to claim after being made redundant, and then left on hold for 40 minutes before being cut off by the service.
Lindsay Kearton, policy advisor for Citizens Advice Cymru, who helped 1,500 claimants for Universal Credit in Wales last year, said some parents had to give up work due to issues with paying child care under the new system.
She told BBC Wales: "Not only are people struggling to make ends meet, to pay their bills, have to resort to turning to food banks, going into debt, borrowing money from family and friends, as well as other credit providers, it's also having an impact on people's ability to pay their rent sometimes, in terms of delays in housing payments, which could potentially have serious consequences."
A DWP spokesman said under Universal Credit people were moving into work faster and staying in work longer than under the old system.
"Universal Credit is designed to mirror the way many people in work are paid and we have budgeting advice and benefit advances available for anyone who needs extra help," he said.
"The vast majority of claimants have told us they are satisfied with Universal Credit.
"We are rolling out Universal Credit in a gradual, safe and secure way and in the rare cases where issues arise, we work closely with local authorities and landlords to support people when they need it."