It is essential that every Australian citizen has a stand-alone proof of their Australian citizenship other than an Australian passport.
The reasons for this include:
- Passports are only valid for a certain number of years
- Australian passports are issued by the Department of Foreign Affairs and Trade (DFAT), while Australian citizenship is the responsibility of the Department of Immigration and Citizenship (DIAC). Issuance of an Australian passport does not create a record on DIAC systems.
- Passports can be easily lost
- Passports are not always accepted as conclusive evidence of Australian citizenship. For example, DFAT normally requires those applying for a first adult passport to prove their Australian citizenship again, even if they had an Australian passport as a child.
- Where your Australian citizenship is contingent on a parent's citizenship or immigration status, privacy laws and in some cases, loss or destruction of archived records may make it very difficult to prove after a long period of time.
 Acceptable evidence of Australian citizenship
Other than an Australian passport, the following normally constitute acceptable stand-alone evidence of Australian citizenship:
- Australian birth certificate, if you were born before 20 August 1986 and there is no evidence to suggest that Australian citizenship was not acquired (eg diplomat parents)
- Certificate of registration or naturalisation as an Australian citizen
- Certificate of Australian citizenship by descent
- If you lost and subsequently resumed Australian citizenship, a letter or certificate from DIAC confirming your resumption.
 Obtaining a Certificate of Evidence of Australian citizenship
- If you do not fall into one of the above four categories, or if you have lost your previous citizenship certificate, you should apply for a Certificate of Evidence of Australian Citizenship
- As at January 2010, the fee is A$60
- Processing time is usually within a month
- The certificate will state that the person is an Australian citizen since a particular date.
 Persons born in Australia since 20 August 1986
- It is very common for migrants to have children born in Australia
- Provided at least one parent is an Australian citizen or is a permanent resident (or is an "eligible" NZ citizen) when the child is born, then child is automatically an Australian citizen.
- The Australian birth certificate is not proof of Australian citizenship
- Many government officials, and others, do not understand that children born to permanent residents and eligible NZ citizens are automatically Australian citizens by birth.
- If neither parent is an Australian citizen then it is very important to document the child's Australian citizenship with a citizenship certificate.
- Even if one parent (or both) is an Australian citizen it is still recommended to obtain separate evidence of the child's Australian citizenship, due to restrictions on obtaining a parent's birth certificate in some states and territories.
 Citizenship under the 10 year rule
- Children who are born in Australia on or after 20 August 1986 and live in Australia until age 10 acquire Australian citizenship on their 10th birthday, if not already Australian citizens
- Immigration status of the child and/or parents is irrelevant
- This is an automatic process but should be documented as soon as possible.
 Other cases where a Certificate of Evidence is required
 Children Naturalised in Australia before 1 July 2002
- Prior to 1 July 2002, children under 16 who became Australian citizens alongside their parents did not receive individual citizenship certificates
- Instead, their names were included on the reverse of the parent's certificate
- Anyone in this position should now apply for an individual Certificate of Evidence of Australian citizenship.
 Persons who migrated to Australia before 26 January 1944
- "British subjects" (ie, those from Commonwealth countries, not just the United Kingdom) who were ordinarily resident in Australia for the 5 years preceding 26 January 1949 normally became Australian citizens on that date
- The only way to prove this is by applying for a Certificate of Evidence of Australian citizenship
 Less usual cases
- Women who were married to an Australian man on 26 January 1949 and had entered Australia before that date
- "British subjects" born outside Australia before 26 January 1949 to an Australian father who migrated to Australia before 1 May 1987, who became Australian citizens on the date of entry to Australia
- Australians born in the former Territory of Papua before 16 September 1975 who retained their citizenship upon Papua New Guinea independence
- Persons adopted in Australia since 22 November 1984 where at least one parent was an Australian citizen and the person was a permanent resident at the date of adoption.
- Some persons born in Australia before 20 August 1986 to diplomats from Commonwealth nations, who if born prior to 24 December 1952 may have acquired Australian citizenship by birth.
- Persons born in the former British territories of the Cocos (Keeling) Islands or Christmas Island, who acquired Australian citizenship by declaration when the territories transferred to Australia in 1955 and 1958.
 Refusal of an application
- If DIAC do not accept that you are already an Australian citizen your application will be refused
- However, if you believe you are an Australian citizen despite the refusal, you may apply directly for an Australian passport. Refusal of an Australian passport can be appealed to the AAT.
- Alternatively you can challenge the decision in the Australian courts.
- A refusal does not prevent you lodging an application to become Australian citizenship, if eligible to apply under another provision.