To clarify, more information on what a plebiscite is.
A plebiscite requires parliament to pass an act to enable a vote to take place.
The enabling act for a plebiscite sets the terms under which the plebiscite is carried out, and the timing.
Sets the question or questions to be put. Needs to be something that can be answered yes or no, otherwise how do you define a win. The wording of the question will be crucial as it can tip the result either way.
Sets whether voting compulsory or voluntary. Opinion seems to be that it has to be compulsory.
Defines how the voting is conducted eg at polling places, by post, online via an app etc, and when, e.g. all on one day, or over a period of time.
Defines what constitutes a win, e.g., a simple majority of all votes cast, a threshold to be reached, e.g. 60% of all enrolled voters etc etc
Plebiscite generally taken to mean a simple vote of all eligible voters, but I can find nothing that would invalidate a requirement to win both a global majority of votes plus a majority of electorates voting in favour. The enabling act sets the exact terms.
Clearly such a double majority would be harder to achieve. Even a simple majority of electorates might be impossible.
We could end up winning a majority of votes cast but a minority of electorates, and so failing.
A plebiscite cannot force MPs to vote on the outcome at all, so the result could be ignored, e.g., Labor could ignore a no vote, the Coalition could ignore a yes vote. Or a decision could be delayed, even indefinitely.
A plebiscite cannot bind an MP to vote in any particular way, though it would be a brave MP who went against the vote of his electorate.
My primary information source is Anthony Green http://blogs.abc.net.au/antonygreen/2015/08/plebiscite-or-referendum-whats-the-difference.html
Any errors are all my own: it’s a confusing subject!