Normally, Australian citizens are required to present an Australian passport when entering Australia. According to Travel documents for entry to Australia:
Australian citizens have an automatic right of entry to Australia, and do not require a visa. Australian citizens need only to present the following documents to officers in immigration clearance:
- a valid Australian passport or other acceptable travel document
- a completed and signed Incoming Passenger Card.
Australians who hold dual or multiple nationalities should hold an Australian passport and use it to enter or leave Australia, even when using a foreign passport overseas. The only exception is where they have been issued with an Australian Declaratory Visa.
The same page has this to say about the Australian Declaratory Visa:
The Australian Declaratory Visa (ADV) is an administrative document that resembles a visa. It is issued in limited circumstances to Australian citizens who hold dual nationality, only if the applicant either:
- is a dual national under the age of 18
- has an emergency or other situation preventing travel on an Australian passport.
The Australian Declaratory Visa is valid for five years from the date of issue, unless the holder ceases to be an Australian citizen, in which case the holder will need a normal visa to travel to Australia.
Charges apply for this service.
The question for you is whether they would consider your situation an "emergency or other situation" that qualifies you to get an ADV. I would call the Australian High Commission immediately and ask them what your best course of action is.