"It's a terrible loss, it's such a tragedy - such a beautiful young girl, taken so suddenly.''
Mr Mundy and his wife, Serena Bowman, had helped Ms Ngatai return to Australia after she had been living on the streets in New Zealand.
"We got her back to Australia, she found Stevie-Ray Cook - the so-called love of her life - and moved back to the other side of the city, and now it's all history.''
Ms Ngatai and Mr Cook had had problems previously, Mr Mundy said.
``We all tried to warn her and make her split up with this guy. But she loved him, always went back to him - it didn't matter what. We all tried, but she just wouldn't listen. What can you do - lock her up?''
Ms Ngatai's three children were aged between 5 months and 3 years.
The eldest has lived with Mr Mundy and his wife since Ms Ngatai signed over custody as a baby.
The other two children, fathered by Cook, are thought to be in the custody of Cook's family.
Ms Ngatai's family in Australia are arranging a memorial service for Monday, after which her remains would be returned to New Zealand.
Her father in New Zealand, Dion Kahukaka, has set up a memorial fund to bring his daughter home and help support her three children.
Ms Ngatai and Cook had reportedly been drinking in the back yard with friends on the night of her death.
Neighbours heard a man yelling "I love you, wake up'' shortly before an ambulance arrived about 2am on Saturday, the Herald Sun reported.
Paramedics could not save Ms Ngatai and she died in hospital a short time later.
Cook appeared in the Melbourne Magistrates' Court on Monday.
