Rugby League star Mitchell Pearce will enter an overseas rehabilitation clinic after being filmed simulating a sex act with a dog while under the influence of alcohol, Sydney Roosters have revealed.

Video emerged on Wednesday of a drunken Pearce interacting inappropriately with the animal, prompting NRL side the Roosters to stand him down from training pending an investigation.

In the clip, which is said to have been filmed at a party on Australia Day, the 26-year-old is also accused of urinating on a sofa before being told to leave the property.

An emotional Pearce apologised for his actions on Friday and acknowledged that he has "a problem with alcohol".

The Roosters have now confirmed the half-back has departed the country to undergo rehabilitation.

A statement read: "The Sydney Roosters can confirm that Mitchell Pearce will be receiving treatment in an intensive rehabilitation facility for an extended period.

"Pearce has tonight [Friday] departed for the overseas facility with his mother, Terri.

"The club's concerns for Mitchell's welfare remain paramount as he seeks treatment."