I did say "in theory". The laws are on the books, there's no legal exemption for "public figures" here, nor does malice need to be proved. Even truth is not an absolute defence, it must be both true and in the public interest to damage someone's valuable reputation.
That's why accusations are usually made under 'parliamentary privilege', which is absolute, anyone can legally spout the most outrageous slander and get away with it (in Parliament).
A Restaurant critic was successfully sued for giving a bad review about five years ago, and truth was no defence for him.
But then again,
politicians have been sued too.
See
Chapter 6 of Information Liberation :
The examples in this chapter are Australian, where defamation laws are notorious for their severity and their use against free speech, and where there is no clear constitutional protection for free speech.
To avoid giving offense, I will not comment on whether we have political 'Freedom of Speech' here or not. I have already done so on
another forum. Oh yes, IANAL, but in the course of my work I did have to review every reported superior court case in every state of Australia over a 5-year period. Checking a Legal database. If you can find any URLs that contradict my belief, I'd be most grateful.