Wallabies Kurtley Beale and Cooper Vuna have been sent home from South Africa following a fracas hours after the Melbourne Rebels slumped to a franchise record 64-7 Super Rugby defeat in Durban.
Beale is alleged to have punched Vuna on the Rebels' team bus following a visit to a local nightspot.
An investigation was conducted the morning after the incident with coach Damien Hill saying they had both broken team protocol.
They will miss the Rebels' clash with the Cheetahs next weekend in Bloemfontein with further disciplinary action a possibility.
"The club will no longer tolerate this type of behaviour and I am embarrassed for everyone associated with building this club," Hill said in a statement.
Rebels chief executive Steven Boland said as both Beale and Vuna were contracted Wallabies it was also a matter for the Australian Rugby Union.
"There can be no excuses for the disrespect shown to the Melbourne Rebels Rugby Club by these players," Boland said.
The incident is understood to have followed an argument between Beale and Rebels captain Gareth Delve after Delve ordered Beale to put his shirt back on before the bus reached the hotel.
Hours after the Rebels' humiliating record 10-try defeat by the Sharks in Durban on Saturday night (Sunday NZT), Vuna tweeted that Beale had punched him.
"I need to leave right now, this ain't for me! I tried to help someone but got punched so instead of putting him in hospital il leave!" Vuna posted at 1.27am local time.
The tweet was deleted about half an hour later but later published on fan website Green and Gold Rugby.
When a Twitter user, named @heart-Madrid, asked Vuna if his alleged assailant "was drunk", the Rebels winger replied: Hmmmmm his name is @kurtley-beale bloody grub!"
Beale didn't play in the match as he continues his recovery from hand surgery but was expected to be available next week while the Sharks game was Vuna's first competition match this season after a shoulder injury.
Vuna, who played two Tests last year, has been on a self-imposed alcohol ban.
Beale is facing assault allegations arising from an incident at a Brisbane night spot last year, in which he was alleged to have hit a bouncer.
The case was sent to mediation late last month, with the first session to take place next month.
Following the embarrassing loss Hill had questioned his players' pride in their jersey following their heavy loss to the Sharks which surpassed their previous biggest defeat of 53-3 by the Queensland Reds in their first year in the competition in 2011.
"Our guys just didn't show up and it's quite embarrassing to be honest," said Hill, with his team 13th on the ladder with one win for the season.
"It's probably the worst defeat I've ever been associated with through the club and I'm really questioning the pride these guys have in the jersey.