We don’t have a properly defined freedom of speech right, although our high court has ruled that we have an implied freedom of “political communication”
https://humanrights.gov.au/our-work/rights-and-freedoms/freedom-information-opinion-and-expression
Which truly doesn’t matter as we are a part of the various treaties and international frameworks mentioned on that site. Treaty law is just as valid as domestic law and as long as that is held we have a right to freedom of speech with the minor caveats of not allowing racist scum to speak freely.