NSW wise you basically need few things if you want to do it by the book

1. permit to own imitation firearms in NSW

2. then to import directly you'll need the following per border force requirements

To import imitation firearms into Australia, police certification in the form of a B709A Form - Importation of Firearms – Police Confirmation and Certification Form is required.

3. the NSW B709 has 2 forms

- Application Form: General Application to Import B709 for Individual or Business (Non-Dealer)
- Ancillary Forms Form: Category A, B & C Firearms and Parts

The forms and are pretty standard and straight forward but NSW has a special requirement where a NSW licensed firearms dealer must be nominated for importation of all NSW unregistered firearms and they will need to pick up the package

Reason being while is a toy it still falls into the following imitation requirement category per NSW firearms reg

*Do I have to nominate a NSW licensed firearms dealer?
If the firearms you are importing are unregistered, you must nominate a NSW licensed firearms dealer to pick the firearm up on your behalf from Customs. In this case the B709 Certificate will be posted to the firearms dealer.