Relevant: the Black Peoples Union position on the referendum (interview on ABC).

An aggregation of written statements collected from socialist, anarchist and radical Indigenous groups, showing the diversity of thought on the matter: http://old.reddit.com/r/AustralianSocialism/comments/161r8r1/megathread_of_leftist_statements_on_the_voice/

(PS: don't just take all the 'yes' and 'no' summaries in that list at face value, a couple of them are misinterpretations or oversimplications)