Running back Larry Johnson has been suspended by the Kansas City Chiefs while they investigate his alleged outburst against head coach Todd Haley and gay slurs made at the media.

Johnson reportedly hit out at Haley's lack of coaching experience during a rant on his Twitter page, while he is also accused of using gay slurs towards the media during a locker room interview.

Both the Chiefs and the NFL are carrying out an investigation into the two incidents and Johnson has been banned from practice and participating in team activities.

With no timescale set on the suspension, Johnson could be out of the picture until the investigation comes to a conclusion one way or another.

"The Kansas City Chiefs and the National Football League are continuing to investigate the alleged comments made by Larry Johnson," read a Kansas City Chiefs statement.

"Until that review is complete, the Chiefs have instructed Larry to refrain from practicing with the Chiefs or participating in other team activities. A decision regarding Larry's status will be made once the investigation has concluded."

Haley will be talking to the media on Tuesday but there are no plans to discuss the Johnson situation during the news conference.

For his part, Johnson released an immediate apology for his actions through his representatives.

"First of all, I want to apologize to the fans of the Kansas City Chiefs and the rest of the NFL, commissioner Goodell, the Chiefs organization, coach Todd Haley, his staff, and my team-mates for the words I used yesterday," the statement read.

"I regret my actions. The words were used by me in frustration, and they were not appropriate.

"I did not intend to offend anyone, but that is no excuse for what I said. I also want to apologise to all the kids who view athletes as role models.

"I was not a good role model yesterday and hopefully I can become a better role model. We all make mistakes, and the challenge is to learn from them.

"I will do my best to learn from this one as I move toward becoming a better person, team-mate, and member of the Kansas City Chiefs team and community."

Relations between starting running back Johnson and coach Haley have become strained with the Chiefs again struggling badly this year, with just one win this season.

Johnson has not been at his best when running the ball but he has criticised the play calling by the Chiefs and questioned the credentials of Haley as a head coach.