The quick and simple answer is YES. There are a number of reasons why you should have your document translated professionally and by a certified translator. One of the reason is if you are submitting your documents to an Australian federal, state or local government authority, they will more than likely request that your documents be translated by a translator who holds a current NAATI certification. If you provide a non-NAATI certified document, your application will likely be rejected and cause delay in your processing time.
NAATI is the only official body for translators and interpreters in Australia. It sets the benchmark of what is expected of any professional translator in Australia.