Scott Morrison has carried an unusual burden for an Australian prime minister campaigning for election.

As well as explaining why Australians should vote for him, he's also had to explain who he is to voters who have had little time to get to know their government's leader. Saturday is the last possible date that Morrison could have realistically chosen to hold an election.

The 51-year-old former tourism marketer was labeled the "Accidental Prime Minister" in August 2018, when he was thrust to the top of a bitterly divided government facing likely defeat in elections only months away.

Opinion polls suggest the opposition Labor party will win despite public misgivings about its leader, Morrison's rival Bill Shorten.