Sephora don’t post to Aus yet this is on their website:
Sephora U.S. currently ships to the contiguous 48 U.S. states, Alaska, Hawaii, Puerto Rico, and to the following international locations: Germany, Japan, Netherlands, Norway, South Korea, and the United Kingdom.
Shipping to other international destinations and U.S territories (such as Guam) is unavailable at this time.
However there is a work-around. You can register for a US address and they ship it to your “address” in the USA, they then receive your parcel – and they will receive multiple parcels for the fee and then box them all up in the one order and ship it to you. So in effect you have a USA mailing address so you can register and pay for your Sephora stuf. I used to buy international a lot but haven’t for about 3 months but I know myusaddress is not the most accepted.
There is Sephora in Malaysia, Singapore and Turkey (I know because I have been to them) so maybe one of those sites will accept your order? I’m guessing Malaysia might be a go it is pretty close. Google “get an American postal address”, have read on the fees (they do the first order very cheap/almost free of fees as a welcome).
I did this frequently and the only thing I would say is don’t have a hugely expensive order, it can cause you some issues with Customs in Aus and you may have to pay duty if you have a high value order.