There is a standard extension accessory cord that can replace the
duck-head toggle AC-in part of the MagSafe adapter, they can vary
in cost but Apple has or had one (I have four or five) that add about
4+ feet of electrical wire between the mains power and the MagSafe.
If the cable idea is adequate, when converted to AU on the mains
end, you probably could buy one already built that way over there;
or, if not, someone should be able to put a new AU plug on the
extension cord in less than 15 minutes while sipping a coffee.
Here's link with the official (US/Canada) MagSafe with duck-head and
AC power cord with the localized part number; there should be similar
part except for the extension AC-in, in the correct Australia configuration.
• Find the right power adapter and cord for your Mac notebook - Apple Support
Note first image shown below is from the link above, and across the different
MagSafe adapter versions, the cord is the same idea...
If such an AC Cord is available from Apple in AU, that'd be the fix...
You could probably get someone with electrical shop skills to replace
the standard US/Canada mains plug end, with an AU specialized plug
for a fee; or perhaps a parts house there sells replacement ends that
almost any hobbyist or repair person could attach to such a power cord
once the original end is removed. The long extension cable is 3-prong
so the ground would be intact.
I've seen images of what appeared as AU replacement duck-head for
use with the Apple power adapters. The AC side of these adapters is
the same now as it was for the older PowerPC (pre-intel) portables.
And the same AC cord is the same for the first generations of AirPort
Express wi-fi base station that uses the duck-head, as it also removes.
I know, I have one of these as well... Someone in Australia should have
one of those original localized AC cords, unless they've all been tossed.
{This topic has appeared here, in ASC, few times in the past 10 years;
& I've wondered why Apple's AU web site doesn't show a local version.}
Sorry this almost sounds like a rant, when it really is another way to look
at the problem. Existing AC cords should exist, official parts. I know there
are a few clones that may not be safe, from China... I've seen images of
them online, while not in the market & unwilling to buy from an unknown.
+The AU-duckhead part/clone may not stay in place; an AC cord is better.
In any event...
Good luck & happy computing! 🙂