Kelly won Song of the Year Tuesday at the International Convention Centre in Sydney for his track "Firewood and Candles" which he wrote alongside Billy Miller of The Ferrets.
"Firewood and Candles" appears on Kelly's latest album Life if Fine, which earned him his first No.1 album in his homeland of Australia. Miller says the song was written during tea breaks while playing cricket, The Sydney Morning Herald reported.
Sia, meanwhile, extended her career APRA wins to nine by winning the award for Most Played Australian Work Overseas for her song "Cheap Thrills" which she co-wrote with Gregory Kurstin.
Ed Sheeran won the award for International Work of the Year for his song "Shape of You" along with his co-writers Kevin Briggs, Kandi Burruss, Tameka Cottle, Steven McCutcheon and John McDaid.
Other big winners included Midnight Oil winning the Ted Albert Award for Outstanding Services to Australian Music, hip-hop group A.B Original winning Songwriter of the Year, Sarah Aarons winning Breakthrough Songwriter of the Year and Peking Duck's "Stranger" featuring Elliphant winning Most Played Australian Work.