Police said they were investigating an alleged assault involving a 71-year-old man and another man on Neutral Bay wharf about 2.30 a.m. on Tuesday. Police did not name Swift's father, Scott, who is 71 years of age.
Local media reported the complainant was an Australian photographer who was waiting for Taylor Swift and her father as they arrived at the Neutral Bay wharf following a late-night cruise on Sydney Harbor.
Taylor Swift was with her father at the time, but had entered a car when the alleged assault occurred, according to state broadcaster ABC.
A spokesperson for Taylor Swift told Rolling Stone two people were acting "aggressively" towards Swift and her entourage when the incident occurred.
"Two individuals were aggressively pushing their way towards Taylor, grabbing at her security personnel, and threatening to throw a female staff member into the water," the spokesperson said in a statement.
The ABC reported the photographer, Ben McDonald, said Swift's entourage used umbrellas to try and prevent him taking photographs and in the alleged altercation Swift's father became involved.
Taylor Swift's Australian leg of her record-breaking Eras tour ended on Monday evening.