Josh Frydenberg is facing fresh questions about a return to federal politics while promoting his memoir, "A Grateful Son." The reception among colleagues has been lukewarm, and Barnaby Joyce was blunt, calling a Frydenberg leadership push "very bad." John Howard drew attention at the book launch with a cheeky remark about his former treasurer's ambitions.

Some political commentators have backed Frydenberg over other potential Liberal candidates, but no formal move has been made public. Frydenberg has also defended the large-scale spending that occurred under his watch as treasurer, putting fiscal policy back on the table alongside the leadership speculation.