I will visit Australia very soon. I bought this gift. Can I have problems with Customs at the Australian airport?
For as far as I can see there are no 'non allowed' parts, like wood, food or medication.
Metal is not blocked from entering Australia.
If there is real value to this, you should report it as valuable, and might be asked to show it as they might want to confirm value and what it is made of.
You may want/need to pack it in your hold luggage if there are sharp points or edges, or if you just want to be sure that security is not going to give you problems.
Where you pack the item does not make any difference for customs as you will collect your hold luggage before going through customs and import security (or whatever it is called officially.)