The union representing welfare caseworkers says a new computer system that administers social assistance in Ontario is creating "chaos."

CUPE spokeswoman Carrie Poole-Cotnam says the revelation that a bug in the software mistakenly queued up 20-million dollars in overpayments to welfare and disability recipients last week was just the tip of the iceberg.

She says the 240-million dollar Social Assistance Management System is riddled with "design flaws" that have workers jumping through hoops just to do basic tasks.

Poole-Cotnam says caseworkers are now spending most of their time struggling to navigate the system rather than doing what they`re supposed to -- helping people.

She adds that welfare and disability recipients are getting the worst of it, with delayed payments and missed opportunities to connect with the services they need.

The ministry says additional staff have been sent to help front-line offices.