Prif Weinidog Cymru sy’n eu penodi er mwyn helpu Gweinidogion gyda materion lle mae gwaith y Llywodraeth a gwaith y Blaid Lywodraethol yn gorgyffwrdd a lle byddai’n amhriodol i weision sifil parhaol fod yn gysylltiedig â’r materion hynny. Maent yn adnodd ychwanegol i’r Gweinidog, gan ddarparu cymorth o safbwynt sy’n fwy gwleidyddol ymrwymedig a gwleidyddol ymwybodol na’r hyn fyddai ar gael i Weinidog gan y Gwasanaeth Sifil parhaol.
They are appointed by the First Minister to help Ministers on matters where the work of Government and the work of the Government Party overlap and where it would be inappropriate for permanent civil servants to become involved. They are an additional resource for the Minister providing assistance from a standpoint that is more politically committed and politically aware than would be available to a Minister from the permanent Civil Service.