As outlined by AQIS, certain goods are not permitted into Australia. Prohibited goods include fresh fruit and vegetables, unidentified seeds or spices, live animals (without an import permit), untreated wood, or goods that are contaminated with soil, such as hiking boots or bicycle tires. If you declare items that are listed as 'prohibited,' you can pay AQIS to treat the goods through fumigation or irradiation to make them safe. If they are not declared, though, you may be penalized and the goods may be destroyed. Your crate will be refused entry.
The shipping company will request a signed Authority to Act form, to give it permission to clear the crate for customs on your behalf; a list of the crate's contents, to prevent prohibited goods from being shipped; a copy of your passport and customs form B534. If you are arriving in Australia after your crate, form B534 allows the shipment to be cleared by customs before you arrive. You'll also need to provide a copy of your visa to show that you have permission to enter Australia. With all these documents, the shipping company can get the crate through customs smoothly on your behalf.
You will need to pay the shipping company to send your goods to Australia, and AQIS will also charge a tax and duty, unless the goods in your crate have been owned and used for a year prior to importation to Australia. In this case, you will be exempt from paying duty and tax. However, AQIS charges to inspect your goods on arrival. The rate starts at AU $80 for a crate up to 10 cubic feet. Crates over 350 cubic feet are charged at AU $260.