Federal politicians have added their voices to the condolences for Port Adelaide footballer John McCarthy who died in Las Vegas during an end of season trip.

McCarthy fell to his death at a Las Vegas hotel on Sunday, Las Vegas time, after being separated from his AFL teammates.

Witnesses watched McCarthy fall from the hotel building about 5.40am (10.40pm AEST) in a fatality which has devastated the AFL.

The AFL and Port remain puzzled at the circumstances of the death of the 22-year-old, who was found on a driveway at the Flamingo Hotel, which was not the hotel where he was staying.

Mark Butler, the federal Labor MP who represents Port Adelaide, said it was a shocking tragedy to lose someone so young with so much promise.

"John was an exciting player with a heap of potential to play an important role in the club's rebuilding in future years," he told parliament on Monday.

"After a tough year this will be a difficult time for the Port Adelaide Football Club and our thoughts are with the club."

He also extended his sympathy to McCarthy's parents, siblings and girlfriend.

Liberal MP Steve Irons, whose son is a rookie player with the Port Adelaide club, passed on a message from the players.

"The player group are deeply saddened and shocked by John's death," he told the lower house.

"They will do whatever they have to do to keep their club the tight knit club that they all play with ... and particularly the player group will support in any way they can the family of John McCarthy."

Mr Irons added his personal condolences.

"For anyone who has experienced the loss of a child whether it be at ... birth or whether it be at the age of 22 or 35, it is a tragic loss," he said.