A young father's life is in tatters after his partner died following the birth of their son, who last night also died in hospital.

Hayden Tukiri watched in horror as his partner Casey Missy Turama Nathan, 20, went from an excited mother-to-be in labour to being whisked by ambulance to Waikato Hospital suffering complications.

Their baby boy, who had been a healthy full-term baby before the labour, was deprived of oxygen during the birth and rushed ahead of the pair to the Newborn Intensive Care Unit.

Last night Mr Tukiri and his family were called back to the NICU because the infant's condition was deteriorating.

Kymani Casey Nathan-Tukiri suffered heart, liver, kidney and brain damage during the birth.

Mr Tukiri was too distraught to speak to the Herald but a family member said the teenager was only just coping with the tragedy.

"He's sort of coping. He's in shock. Hayden has to deal with everything."

The 18-year-old was at Birthcare Huntly on Monday with his girlfriend of three years as she endured a 10-hour labour.

"As far as we know the labour was going fine until the very end," the family member said.

The woman, who did not want to be named, said it was unclear what the complications were but the family were unaware of any pre-existing medical conditions.

"We're only guessing as to what happened. She was a healthy normal young mum-to-be. She really looked great but they didn't know if she had something hidden."

After the delivery at 11am Miss Nathan, who was worried about her baby, was taken to Waikato Hospital.

She had been conscious but died there several hours later.

Only a week ago Miss Nathan posted on her Facebook page: "O.M.G 3 Days left to go B4 i have baby YAY ".

The family member said both she and Mr Tukiri were eagerly awaiting the arrival of their first child.

"They both had it plastered all over Facebook. They both were so excited."

Birthcare Huntly general manager Ann Henson said nothing like this had happened before at the centre, established in 1995 and operated by Birthcare Auckland.

"It is tragic and our sympathies go to the family."

She said staff were preparing a report on the labour for Coroner Gordon Matenga and she could not say any more.

Detective Sergeant Michele Moore of the Waikato Coronial Investigative Team said police were awaiting the results of a post-mortem examination but that the case was now before the Coroner.

She said police involvement in the case was standard.

"No conclusions in relation to the nature of death should be drawn by routine inquiries of this nature."

The Herald understands Miss Nathan was the youngest of four children.

Her Facebook page lists her as a past pupil of Ngaruawahia High School but as living in Hamilton.

Her family were unable to be contacted for comment last night but it is believed they were making arrangements for Miss Nathan's tangi in Waingaro. Her funeral would take place tomorrow.

Hamilton man Robert Barlow, whose son Adam died during a botched birth in October 2009 and wife Linda almost died, offered sincere condolences to the family.

"It's different circumstances but it's mirrored to the circumstances I was in. Our hearts go out to the family."