NAATI stands for "National Accreditation Authority for Translators and Interpreters".
It is an organisation responsible for setting, maintaining and promoting high professional standards for the Translating and Interpreting sector.
A NAATI-certified translation is one which has been done by a translator that has a NAATI certification. Most Australian authorities require translations of documents to be NAATI-certified.
All NAATI-certified translations include a NAATI translator’s stamp, signature, and practitioner ID.
My (Jan Hein’s) practitioner ID is: CPN0YV89A
To verify my certification, go to NAATI’s official page and type my Practitioner ID where it says "Verify a certification".