Asian Australian voters moving their support away from Anthony Albanese look set to be critical to the Indigenous Voice to parliament result, as a leading election analyst warns multicultural voters unhappy with Labor could sink the referendum.

With hundreds of thousands of early votes already cast ahead of the October 14 poll, analyst and Australian Development Strategies chairman John Black said a “significant sea change” was evident for Labor between the Aston byelection in April and the Fadden byelection in July.