SYDNEY, Australia — Hong Lim, a dapper Australian politician who seems most at home walking the corridors of the colonial-era State Parliament of Victoria in a tailored suit, is not the first person you would imagine burning an effigy in a parking lot.

But the Cambodian-born legislator has now done so twice in recent weeks, after finding himself at the center of an unfolding battle over free speech and the reach of Cambodia’s authoritarian government into diaspora communities in Australia.

In advance of a high-profile visit to the country over the weekend, Cambodia’s long-ruling prime minister, Hun Sen, prompted international outrage by publicly threatening violence against anyone who protested his presence by burning his effigy.

Mr. Lim, 67, said the threat had given him an idea. “Out of the blue, he just said, ‘Look, if you’re going to protest and you burn my photo or my effigy, I’m going to come follow you and go to your house and beat you up,’ ” Mr. Lim said.