Relaying Muriwai's pleas to the court, counsel Sam Wimsett said the crash was "a terribly sad situation". Muriwai had been struggling with his mental health since.
Two specialist medical reports previously ordered by the court differed in their findings as to whether Muriwai was fit to plea but a third one found he was, Wimsett said.
Muriwai was attending counselling and was engaged with appropriate programmes.
He accepted a term of imprisonment would be the sentence starting point but it was hoped the final sentence imposed could be one of home detention, Wimsett said.
Judge Greg Davis scheduled a two-hour sentencing hearing for April 1 and further remanded Muriwai on bail with a condition forbidding him from driving after consuming alcohol.
The case was referred to the restorative justice process.
Muriwai has no previous criminal history.
