The Sydney Morning Herald online said that more than 50 images show Packer and David Gyngell throwing and receiving punches and wrestling on the ground on Sunday afternoon.
Bondi resident Chris Walker, who says he witnessed the incident, tweeted about a "massive street fight" outside Packer's multi-million dollar home.
"Holy crap, big street fight outside my house ... Not thugs, James Packer ... And some other angry bloke going toe-to-toe - total brawl ... Wow"," he said.
The Sydney Daily Telegraph said "a bidding war has broken out over sensational photos showing billionaire gaming mogul James Packer engaging in a fist fight with his former friend, head of Nine Entertainment Group David Gyngell".
Nine said it would issue a statement later Monday.
The Herald said Gyngell was waiting outside Packer's house as the casino mogul was chauffeured home after arriving aboard his private jet at Sydney Airport.
It cited witnesses saying no pleasantries were exchanged when Packer saw him, but rather a flurry of profanities broke out before punches started flying. They were eventually pulled apart by a bodyguard, the newspaper said.
Reports said the pair's life-long friendship soured after Packer and his second wife, Erica, separated six months ago.