Yes, the commencement of a registered relationship under the Relationships Register Act 2016 (SA) automatically revokes a will unless the will was made in contemplation of the registered relationship and this was stated in the will. In contemplation of the registered relationship means that the testator was planning to commence the registered relationship at the time of making the will, and the will is made with this in mind.
The end of a registered relationship, under the Relationships Register Act 2016 (SA), revokes any bequest to the former partner or appointment of the former partner as executor unless it is clear from the will that the end of the registered relationship is to have no effect.
It is wise to seek legal advice about a will after commencing a registered relationship.
See sections 20 and 20A of the Wills Act 1936 (SA).