Sam Powell-Pepper is the AFL player under investigation for an alleged incident on Sunday morning at an Adelaide bar.
Channel Seven reported that a woman alleges the Power midfielder put his hands up her skirt.
The club issued a statement late on Monday, confirming an investigation is underway.
"Port Adelaide are investigating an allegation one of their players was involved in an incident at an Adelaide bar on Sunday morning," they said.
"The club has advised the AFL and will not be making further comment until it has all the information at hand."
SA Police said on Monday night they had not received any complaint related to the alleged incident.
Port recruited Powell-Pepper as a first-round selection in the 2016 national draft and he had an immediate impact last season, finishing third in the Rising Star award.
He has played 25 senior games and was in the senior team that beat Brisbane by five points on Saturday at Adelaide Oval.
