American swimmer Michael Phelps, the most decorated Olympian of all time, has been suspended for six months by USA Swimming following his recent arrest on a drunken driving charge.

Phelps, who recently returned to top-level competition after a two-year retirement, will also not be allowed to represent the US at the 2015 FINA World Swimming Championships in Russia next August, USA Swimming said in a statement.

The arrest last Tuesday marked the second time the 29-year-old Baltimore-area native had been arrested for drunken driving, the first being in 2004. In the first case, he pleaded guilty to a lesser charge of driving while impaired in exchange for 18 months' probation.

"Membership in USA Swimming, and particularly at the National Team level, includes a clear obligation to adhere to our Code of Conduct," USA Swimming Executive Director Chuck Wielgus said in a statement. "Should an infraction occur, it is our responsibility to take appropriate action based on the individual case. Michael's conduct was serious and required significant consequences."

Phelps apologised for the incident and said on Sunday he was checking himself into rehab for six weeks in order to "better understand myself."

Source: Reuters