From the Home Affairs website:
"A subsequent entrant application can be made using Immi Account if you were declared as a family member on the original application. Log in to Immi Account to find the Subsequent entrant application.If you were not included in a previous application you may need to apply for a child visa."
My own interpretation is a new child visa since as a newborn you could not have mentioned them in your initial application but I could be wrong
"A subsequent entrant application can be made using Immi Account if you were declared as a family member on the original application. Log in to Immi Account to find the Subsequent entrant application.If you were not included in a previous application you may need to apply for a child visa."
My own interpretation is a new child visa since as a newborn you could not have mentioned them in your initial application but I could be wrong