As usual, I would like to remind you that the laws and regulations differ between the different states and territories in Australia.
Basically, there are 2 kinds of teachers.
1. Primary School Teacher
These teachers teach all subjects to the students in a classroom. There are no subject-specific teachers.
2. Secondary School Teacher
These teachers teach a specific subject, like Math, Science.
To be qualified as a teacher, you need to pass IELTS with a score of 7.5 and get a Masters degree in Teaching.
This is some basic information. You need to check with the relevant regulatory authorities about the details.
For more information on the subject, please check out the NSW pgae:
https://educationstandards.nsw.edu.au/wps/portal/nesa/teacher-accreditation/apply/moving-to-nsw