One-term Labor prime minister Kevin Rudd has wished former Victorian premier Ted Baillieu well on "what is a difficult day in someone's life".
Mr Baillieu was late on Wednesday replaced as Victorian Liberal leader by Denis Napthine after he resigned as premier.
Mr Rudd, who stepped aside as prime minister in 2010 to allow the federal Labor caucus to elect Julia Gillard unopposed, said politics is a difficult life.
"At a personal level, though, could I simply say that politics is a very difficult life and to Ted Baillieu and his family our best thoughts and wishes go through to them on what is just a difficult day in someone's life," he told a conference in Melbourne on Thursday.
Federal coalition environment spokesman Greg Hunt said it was wrong to draw comparisons between Mr Baillieu's departure and the Labor government's dumping of Mr Rudd.
"A couple of people have asked the question, whether or not there's any comparison with what the federal government under Julia Gillard and Kevin Rudd did," he told reporters in Melbourne.
"There's no comparison, Julia Gillard has a knife in her hands. Denis Napthine has no knife in his hand."
Dr Napthine said the difference between his ascension to premier and Ms Gillard's rise to prime minister was that he had a united team.
"We don't have blood all over the floor and we didn't stab in the back an incumbent prime minister against their wishes," he told ABC radio.