So any power that is not listed in the constitution automatically becomes a power of the states. One such area is criminal law. If the states want to, they can give up these powers and give them to federal parliament. This is what the referring of power is.
It's rare that this happens, I mean, who wants to willing give away their power? But it did happen sometime in the past decade. You see Federal Parliament deals with the break up of relationships but de facto relationships were a power of the state. To make it easier the states gave up this power to the commonwealth so that the break up of all marriage/relationships could be dealt with together in the one place.
That's what I was thinking, "who wants to willing give away their power?". Is that as much as you would need to say for this point? Just give an example that shows a state giving up a power to the Commonwealth?
I really should have done this before I answered the first time but anyway. I searched through my computer files to find my personal notes from the year. This is what I had on referred powers. You would never need to write more than this.
Referral of Power• S.51 of the constitution gives the commonwealth parliament power to make laws on powers referred to it by state parliaments
• States have given power in relation to the break up of de facto relationships
• Parliament previously had the power to legislate on marriage and divorce, but de facto relationships remained a residual power
• Referred the powers so that de facto relationships could be resolved in the Family Court, which was a federal court
However if you ever have a big question about changing the constitutional powers it would be easier to answer with referendum and/or high court interpretation. Just because there's more to say about them.