Welsh housing association tenants on Universal Credit are in more than two million pounds worth of debt.
The figures released by Community Housing Cymru show the average tenant claiming Universal Credit is in rent arrears of over £400.
A survey of nearly 7,000 people found 23% of them were not in arrears before they transferred to the new benefits system.
Universal Credit, which merges six benefits into one, has been introduced to 11% of claimants in Wales with the UK Government planning to transfer a further 350,000 households by 2023.
Andrew Hustler was laid off as a security officer in August and did not receive any money from Universal Credit until September 14.
Community Housing Cymru are calling for the UK Government to ensure the policy is fit for purpose before introducing it to more people in Wales.
The Department for Work and Pensions (DWP) said the cause of rent arrears cannot be attributed to a single cause.