The Melbourne event will be the hybrid concept's second major event, following its global unveiling at April's New York Auto Show.
Billed as a technical and design study, the LF-Gh is believed to represent a look at the next GS sedan. With the current model now into its sixth year, a new fourth-generation GS cannot be far away.
Among its styling features are Lexus LS-inspired three-bulb headlights, and a new 'spindle' grille pattern. The rear end sees sharp LFA-inspired tail-lights flanked by slotted vents and two trapezoidal exhaust tips.
"The LF-Gh grille really is a powerful design element in its own right - it will become a signature Lexus design element," Lexus Australia boss Tony Cramb said.
"Our latest vehicle, the CT 200h, hinted at where we were taking our L finesse design philosophy, but LF-Gh leaves no questions about what is next for Lexus."