He lived in the North Island, but was on a video call with her.
"He's hammering her, he's hammering her ... can someone please help her, 'cause that's my daughter," the father said on the call, which was played to the jury.
However, he testified in court that he could not remember any of that night because he and his wife were drinking.
By 11.35pm, two constables, including Constable Deirdre McKenna, arrived at Paul's house. In her testimony to the court yesterday, McKenna said they heard a male yelling when they approached the home.
After receiving no response to knocking, they decided to enter.
Paul exited the room at the end of the passageway holding a hammer but dropped it after being asked twice.
When McKenna asked why he had the hammer, Paul replied that it was from an earlier incident with his neighbours, who were banging on the wall. Paul was then asked about the woman's parents seeing him assault their daughter over the phone.
"Honestly, look at her legs and see if I hit her repeatedly with a hammer. I did not hit her ... that's the honest truth," he answered.
When she saw the complainant, McKenna made note that she could see redness on the woman's right cheekbone and a bump above her right eye.
However, in cross-examination, counsel Alan de Jager said a constable who spoke to the complainant the next day did not see such injuries.
McKenna agreed that although she saw blood on a pillow and duvet, as well as on a hoodie the complainant was wearing, she did not analyse them or seize them for testing.
"I was dealing with Mr Paul," she testified.
The hammer was also never tested.
The defence's case was that Paul did not assault the complainant that night, de Jager said.
He asked the jury to treat the father's evidence with caution as he was intoxicated and watching from the North Island on a cellphone.
When the complainant entered the witness box, she testified she could not remember the night very well.
"It ain't my blood," she said when Power asked her about what Constable McKenna saw.
"How was your face?" he asked, in regard to injuries described by the constable.
"Sweet, my whole face, my whole body."
The trial, in front of Judge David Robinson with a jury of 10 men and two women, continues.