Maija suffered fatal injuries when she was in the sole care of Duff after he and his then 18-year-old partner, Melina Puhi, argued.
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Justice Downs said Maija was "plainly loved" and it appeared Duff was a loving father up until the night she died.
Earlier in the day she died, she had spent time with family members and was healthy.
Maija was then taken to her father and left in his sole care. Melina Puhi was elsewhere.
Overnight, Duff inflicted the injuries but - given his claims of not knowing how those injuries were suffered - no one knows how or why.
"Only you know exactly how she died."
Justice Downs said the injuries would have caused immediate unconsciousness, but Duff chose to do nothing and not get medical care immediately and this was an aggravating factor.
"You did not even try."
Justice Downs detailed Duff's significant history of violent offending including being jailed for wounding his former partner with intent by hitting her several times with a hammer, breaking her pelvis.
He had been jailed several other times including for presenting a firearm at a law enforcement officer, wounding with intent, aggravated robbery and two assaults with intent to injure.
Duff was described as a methamphetamine user who had a poor childhood with his mother. However, Justice Downs said he strayed from the care offered by his grandparents and instead turned to the Mongrel Mob, where he became a patched member.
In sentencing Justice Downs said Duff's situation was all too familiar.
"Too many children in this country die because of violence in the home."
Maija's mother was not present in court and the court heard she was too upset to complete a victim impact statement.
"No parent should have to bury their child."
Other family members were in the public gallery at court and were in tears as Justice Downs delivered his sentence.
Two family members provided the court a victim impact statement. They described how heartbroken they were and it was "soul destroying" that she did not die of natural causes.
Amanda Gordon appeared for the Crown and Moan Dorset appeared for Duff.