Yn ôl y gyfraith, rhaid i bob awdurdod lleol ddarparu ‘’llais’’ proffesiynol annibynnol, a elwir yn eiriolwr, ar gyfer pob plentyn a pherson ifanc sy'n derbyn gofal ac sy’n gadael gofal a phob plentyn sydd mewn angen. Dylent gael gweld eiriolwr pan fydd penderfyniadau'n cael eu gwneud yn eu cylch, neu os ydynt am wneud cwyn. Mae Llywodraeth Cymru wedi cyhoeddi canllawiau clir ar gyfer awdurdodau lleol ar ddarparu gwasanaethau eiriolaeth - Darparu Gwasanaethau Eiriolaeth Effeithiol i Blant a Phobl Ifanc sy'n Gwneud Sylwadau neu Gwyn dan Ddeddf Plant 1989.
By law, every local authority must provide an independent professional "voice", also known as an advocate, for every looked after child and young person, care leaver and child in need. They should have access to an advocate when decisions are being made about them or if they want to make a complaint.  The Welsh Government has issued clear guidance for local authorities on providing advocacy services – Providing Effective Advocacy Services for Children and Young People Making a Representation or Complaint under the Children Act 1989