The association for social workers says Child, Youth and Family (CYF) is being confronted with more notifications than ever before and staff on the front line can't cope.
The agency says notifications have quadrupled in the past eight years to more than 150,000 a year.
Association of Social Workers chief executive Lucy Sandford-Reed says social workers cannot meet the demand or higher standards of investigation as cases become more complex and difficult.
CYF general manager of operations Paula Attrill says the Government has increased the number of frontline social workers by 80 in the past 12 months.
Ms Attrill says there's always more work to do than they have people available to do it.
Children Commissioner Russell Wills says the agency's staff have higher caseloads than in many other countries.