The youngest child of four and the only girl, Teiria became involved with the man at the end of August and had told her mother he could provide for her and give her everything she needed.
"I don't agree with the relationship - what parent would?" Mrs Wharepapa said.
The day before Teiria disappeared, she told her mother she and her boyfriend had broken up. "So I thought, 'Okay, I can relax now and stop worrying'. And then she didn't come home from school," she said. "When she wasn't home by 6pm I knew she had run. I went into her room and that's when I noticed that certain things were missing."
Teiria's hair straightener, jeans, cellphone charger and DC-brand shoes were missing.
"It doesn't take a genius to work out ... she's with him," Mrs Wharepapa said.
She begged her daughter to "come home, just come home".
Senior Sergeant Ed Van Den Broek said police had "serious concerns" about Teiria and believed she might be in Gisborne or Wairoa, where her boyfriend had connections. Anyone with information should call the police on (07) 348 0099 or confidentially on (0800) TIPOFF.