Barton was shown a straight red card for a wild tackle on Xabi Alonso during Newcastle's 3-0 defeat by Liverpool on Sunday.
Stand-in manager Alan Shearer condemned the challenge, saying Barton had let down himself and the club. Local media reported that Shearer had rowed with the player in the dressing-room after the match and fined him two weeks' wages.
"Newcastle United can confirm that Joey Barton has been suspended from the club until further notice," the club said in a statement on their website.
"The club will be making no further comment on the matter at this time." Barton, who joined Newcastle for 5.8 million pounds from Manchester City two years ago, was making his first appearance since January after recovering from a foot injury.
"I thought he could do something different," Shearer said after the game. "But I didn't think he'd go on and get a red card. I'd asked him not to do that."
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