If Anthony Albanese, current prime minister, is in support of and vowed to install the Indigenous Voice advisory board, why can’t he just do it? He also made a comment beforehand that he would respect people’s decision if they vote no, implying that he might be able to override it if he wanted to.
"the PM on Sunday said Labor would “respect the response of Australians next Saturday”.
“If Australians vote no, I don’t believe that it would be appropriate to then go and say, ‘Oh, well, you’ve had your say, but we’re going to legislate anyway’.”
I personally believe that what white Australians want is irrelevant to the fundamental rights that the original owners of this land deserve, and he should have just done it if he was able to.
If he truly believed it was a good thing he should have just legislated it to start off with. That way you have the benefits of such a body sooner, and if people can see something in action and actually working to close the gap they would be more inclined to allow it into the Constitution in a later referendum (and even if the later referendum fails you still have both the body and the work they have done).
Edit: To be clearer, it is possible to both legislate a voice and have a referendum on it while a party is in government, particularly since it is rare for a government to only get a single term.