More than 550 children in state care are waiting for a social worker to be assigned to them.
According to Tusla's latest figures, just over 5,000 children who are living in the community are awaiting to be allocated a social worker.
622 of those children are deemed 'high priority' cases.
Another 565 children, who are currently in state care, have also not been allocated a social worker.
Suzanne Connolly, the chief executive of Barnardos, said the stats are a big concern.
"In terms of children in care, by not having an allocated social worker Tusla are not fulfilling their statutory responsibilities," said Ms Connolly.
"We know that Tusla has a problem with recruiting and retaining social workers so it's essential that they address that.
"Because children in need deserve the service to keep them safe and protected."
A further 689 people who suffered abuse in the past are waiting to be allocated a social worker.
Anne Rabbitte, Fianna Fáil's spokesperson for children, said she is "very disappointed" by the figure.
She added: "These are adults that have actually come forward.
"And I can't imagine what it has taken for someone to come forward and to say that 'when I was younger, that I was abused'.
"To think, their voices aren't being heard and we have over 689 awaiting the attention of social workers."
Tusla's stats show 881 people who suffered abuse in the past have been allocated a social worker.