It has been reported that the 51-year-old has allegedly threatened to harm Malin Hylland between January 3 and 4.
It is believed the former couple, who were together for three years, separated in 2018.
The Daily Telegraph reported that the lifeguard, known to viewers as Kerrbox, was arrested at his home before he was taken to Waverley Police Station.
Kerr could not be reached by the Daily Telegraph for comment.
Kerr was charged with stalking or intimidation with intent to cause fear of physical harm.
He also received an apprehended domestic violence order.
He has been granted bail and will face local court on Thursday.