The MLA said it was yet another reason why there must be a halt on its further roll out across the North of Ireland.
The party’s deputy leader was commenting following concerns raised about the issue by the Child Poverty Action Group.
“Working families are losing out on hundreds of pounds of entitlement to Universal Credit over the course of the year because of the date their pay day falls.
“Those paid every two weeks or paid twice in one calendar month are being penalised.
“Not only does this leave claimants financially worse off, but it can also affect health care entitlements and automatically triggers the benefit cap, despite the fact they are working.
“This harsh reality facing working families couldn’t be further from the government’s promise that ‘Universal Credit will help make sure you are better off in work than on benefits’.
“My colleague Patsy McGlone and I have raised this issue with the Department for Communities a number of times.
“Still no action has been taken to resolve this.
“The fact that the system can’t cope with this is further proof that the system is not fit for purpose and at minimum must be halted, if not scrapped,” she added.