"She said he'd been holding her throat."
The girl said her attacker spoke Samoan and had medium-length, wavy black hair. He was wearing a red and black top and black rugby shorts. The man appeared to be on foot and familiar with the area, Tiernan said.
Family and friends were supporting the girl and she was "improving", he said.
Police had spoken with residents and would interview the girl this week.
He was not aware of any similar incidents in the area, but would check for any link with another alleged attack south of One Tree Hill on Friday. Police are investigating after a woman told them she was indecently assaulted at the Oranga School grounds about 4pm.
She told police a Polynesian aged in his 20s attacked her. The man was said have facial acne and the word "TOA" tattooed on one of his hands.
He was wearing a black hoodie with a logo on the front, dark jeans and white shoes.