BBC: Australian Prime Minister Scott Morrison has called a federal election for 21 May.
Mr Morrison's ruling coalition holds 76 seats in the House of Representatives - the minimum needed to retain power.
Polls suggest there will be a change of government, with the opposition Labor Party, led by Anthony Albanese, tipped to take office.
However, in the last election, the centre-right Mr Morrison won despite most polls predicting otherwise.
Mr Morrison announced the date after talks with the Governor General in the capital, Canberra.
"It's a choice between a strong future and an uncertain one. It's a choice between a government you know and a Labor opposition that you don't," the prime minister said on Sunday.
But Mr Albanese - pointing out Mr Morrison's own deputy prime minister called him "a hypocrite and a liar" - argued that "we can and must do better".
"The pandemic has given us the opportunity to imagine a better future and Labor has the policies and plans to shape that future," he said on Sunday.
Mr Morrison is the first leader to serve a full term in office since John Howard, who won four elections before losing to Labor's Kevin Rudd in 2007.
Since then, what observers call the "coup culture" of Australian politics has led to a series of short-lived premierships.
Mr Morrison's Liberal-led coalition is defending a one-seat majority. Even though it has won seven of the past nine federal elections, it may be hard-pressed to do so again, say political analysts.
In recent weeks, the prime minister has faced accusations of being a bully and once sabotaging a rival's career by suggesting the man's Lebanese heritage made him less electable. Mr Morrison has denied the allegations.
But despite the most recent polling putting Labor ahead, Mr Albanese has called his opponents the "favourites", noting his party has only won government from opposition three times since World War Two.