On 13 December 2023, the Australia Customs (Prohibited Imports) Regulations were updated. The following substances were added to Schedule 4:

1. Brorphine

2. Isotonitazene

3. Metonitazene

4. CUMYL-PEGACLONE

5. Diphenidine

6. Eutylone

7. MDMB-4en-PINACA

8. 3-methoxyphencyclidine

9. 4-AP (N-Phenyl-4-piperidinamine)

10. 1-boc-4-AP (tert-Butyl 4-(phenylamino)piperidine-1-carboxylate)

11. Norfentanyl