Diwygiodd Deddf Cymru 2017 Ddeddf Cynrychiolaeth y Bobl 1983 ac mae'n atal cynnal etholiadau llywodraeth leol ar yr un diwrnod ag etholiadau cyffredin i'r Cynulliad Cenedlaethol. Mewn sefyllfaoedd o'r fath, mae angen i Weinidogion Cymru newid blwyddyn etholiadau llywodraeth leol drwy Orchymyn.
The Wales Act 2017 amended the Representation of the People Act 1983 and prevents local government elections from being held on the same day as the ordinary elections to the National Assembly.  In such situations the Welsh Ministers are required to change the year of the local government elections by Order.