It depends on the alocasia. Some are hardier than others when it comes to cold. I've found that my Alocasia macrorhizza albo-variegata will suffer damage at 50 and below, whereas my Alocasia wentii, Alocasia portodora, Alocasia odora, Alocasia gageana, Alocasia machrorhizza plain green, and Alocasia Kuching Mask and the other Kuching series do not. Alocasia plumbea nigra 'Metallica' also is not happy at prolonged temps of 50 and into the 40's and just disappears and goes dormant... neither is Alocasia 'Serendipity happy. So I take those into the greenhouse in winter. And my Regal Shields is more cold sensitive, most likely from the Alocasia reginula 'Black Velvet' parentage.
All alocasia are NOT created equal, just as not all Philodendrons and Anthuriums and many of the plants and hybrids that are specific to tropical AUSTRALIA where the OP is from, and which are not available here in the USA, are adapted to a very specific climate. There are high elevation species that can be totally happy at 50 and even 40, but lower elevation species and hybrids, maybe not so much.
My best advice to you is to talk to locals who live in the area you are moving to. I know a lot of aroidists that live in the more tropical parts of Australia, aroidists are kind of like a club, like the people on here who grow day lilies or cactus like stuff... we are genera specific people who concentrate on aroids and they do tell me that there are significant differences in climate in Australia. What flies at the coast does not always fly anywhere else.
Don't rely on advice from people in the USA who do not know the particulars of your specific climate zones there. Talk to locals, see what they have growing where you are moving, and what they do or don't do to grow their plants.
