Prime Minister Anthony Albanese says he's still in shock at news of the assassination of Shinzo Abe.
"The friendship the former Japanese prime minister offered Australia was warm in sentiment and profound in consequence," Mr Albanese said on Saturday.
"No one was more committed to furthering relations between our two nations."
Mr Abe, 67, was shot and killed while campaigning near a train station in the Japanese city of Nara on Friday. A man was arrested at the scene.
Mr Albanese said Mr Abe, who visited Australia five times as prime minister, was instrumental in delivering several historic agreements and elevated relations between the two nations to a special strategic partnership.
He also noted Mr Abe addressed both houses of parliament in Canberra in 2014 and four years later became the first Japanese leader to visit Darwin, which was bombed by Japan during World War II.
"Mr Abe was a great statesman who made a difference," Mr Albanese told reporters in Canberra.
"His vision of a free and open Indo-Pacific had a profound effect on regional and global security."
According to protocol, official Australian flags will fly at half-mast on the day of Mr Abe's funeral.
Major landmarks will be lit in red and white in Melbourne on Saturday night as a tribute to Mr Abe, as will Adelaide Oval and South Australia's parliament.
A similar display will involve the Sydney Opera House on Sunday.
Meanwhile, the Australian Olympic Committee has hailed Mr Abe as a great friend to the global sporting movement.
AOC President Ian Chesterman said the success of the Tokyo Games during the COVID-19 pandemic was a tribute to his leadership and perseverance.
"We are deeply saddened by the loss of Mr Abe," he said.
"The Tokyo 2020 Olympic Games were such a triumph, giving hope and inspiration to so many around the world."
IOC Vice-President John Coates worked closely with the then prime minister in his capacity as chair of the IOC Coordination Commission for the Tokyo Games.
"Without Shinzo Abe's commitment, the decision to postpone the Games by one year in the face of the global pandemic would simply not have happened," Mr Coates said.
"All of the athletes of the world who participated in the Tokyo 2020 Games are forever indebted to him."
Business Council chief executive Jennifer Westacott said Mr Abe was a visionary leader in the Indo-Pacific and "a champion of a freer and more open world".
