Essentially, original without notarisation (OWN) is where a document is sent directly to the Department of Foreign Affairs and Trade (DFAT) without a notarial certificate signed by an Australian public notary that’s bound by black ribbon & notary seal attached to it. DFAT instead applies either an apostille stamp (for use in countries that are a party to the Hague Convention) or an authentication stamp (for use in countries that are not a party to the Hague Convention but require further attestation by the relevant Embassy/Consulate in Australia) to the original document. The relevant overseas authority requesting you apostille/attest your document will (or at least should) instruct you of the correct requirements.
Only original Australian university degrees/transcripts, original police certificate issued by the Australian Federal Police & original Australian documents (including birth, death and marriage certificates) issued by Registry of Births, Deaths & Marriages can be done through OWN. If someone picks OWN on an ineligible document, DFAT will say to get it notarised & DFAT will not stamp something ineligible. It may also mean you incur additional time, professional fees &/or disbursements to carry out your request. If you are unsure about eligibility for OWN &/or would like more information, please contact us at email@example.com.