Brisbane Broncos duo Payne Haas and Albert Kelly have been allegedly videoed in a drunken fist fight outside a pub.

The footage, which surfaced on Twitter on Sunday evening, allegedly videos the duo outside of a Sydney establishment after Brisbane's Round 2 victory over the Canterbury Bulldogs.

The Broncos have told The Sydney Morning Herald that they are aware of the footage, have referred it to the NRL's integrity unit and are now in the process of conducting their own internal investigation, which will continue over the coming days.

The NRL also confirmed to the publication that they have seen the video, are aware of it and will join the Broncos in investigating this week.

The 13-second clip appears to show the much larger Haas growing angry at Kelly, who asked Haas "Why would I step on your shoes," before repeating that he wouldn't step on the prop's shoes after a strike to his face from Haas' left fist. That was followed with Haas shoving Kelly in the face again, the second occasion being with his right hand.

Should the NRL confirm the vision it could spell bad news for Haas, who has had two prior involvements with the NRL's integrity unit totalling seven matches worth of suspensions and $70,000 worth of fines.

The first four games and $20,000 was for refusing to cooperate with an integrity unit investigation ahead of the 2019 season, while the remaining three games and $50,000 was for a tirade at police last year in Tweed Heads.

The timing of the video couldn't be worse for the Broncos, who have been left reeling after back-to-back losses to the North Queensland Cowboys (38-12) and the New Zealand Warriors (20 points to 6).

Kelly is set to spend the next three to five months on the sideline anyway, having suffered a lisfranc fracture to his foot during Saturday's heavy loss to the Warriors, while Haas, consistently Brisbane's best player, is under constant speculation regarding his future, despite not being off-contract until the end of the 2024 season.

He has been linked with both the Sydney Roosters and Canterbury Bulldogs as he seeks a mega contract upgrade from the Broncos, with the New South Wales State of Origin prop reportedly likely to sign a deal worth around $1 million per season.

The Broncos can ill-afford to be anything other than full strength in the coming weeks, with the club set to take on the Sydney Roosters and Penrith Panthers in the next fortnight.