The man, 51, alleged Scott Swift, 71, assaulted him at Neutral Bay Wharf at about 2.30am today.
The pop star played her final Sydney show last night, wrapping up her seven-night Australian tour.
“Police are investigating an alleged assault on Sydney’s North Shore this morning,” NSW Police said in a statement.
“Police have been told a 71-year-old man allegedly assaulted a 51-year-old man at Neutral Bay Wharf about 2.30am, before leaving the location.
“The younger man reported the incident and inquiries are now underway by officers attached to North Shore Police Area Command.
“The man did not require medical treatment.”
Scott Swift has been no stranger to the limelight over the past fortnight and was seen supporting his daughter throughout her sold-out tour.
Affectionately known by Swifties as “Papa Swift”, he has been captured on more than one occasion handing out his daughter’s guitar picks to adoring fans.
He also gifted surprise VIP passes to a mother-daughter duo who were sitting in restricted viewing seats at the MCG.
Scott went around and handed them wristbands and entry into the VIP section, according to the lucky fan.