"This is yet again another tragic loss of life of a baby which has most likely occurred during an unsafe sleeping environment/co-sleeping with others," Mr Smith said.
"Despite the coroners and other health advisers continually advising that such practice is often fatal, families continue to put their children at a fatal risk."
Mr Smith said a midwife had visited the family's home on several occasions after the baby girl was born and "discussed such matters as sleeping arrangements for the baby".
On one visit the baby was placed down on a couch with an adult-sized pillow and her parents were told it was "very unsafe" because of a risk of rolling over and suffocating, Mr Smith said.
His finding follows an inquest this week which was told a Tauranga 2-month-old likely suffocated after slipping from its pillow last year.
There were about 60 cases of SUDI in New Zealand each year and just over half were the result of bed sharing with another person.
Twenty babies died each year of SUDI in South Auckland alone, largely in Maori, Pacific Island and low income families.
• Sleep baby in their own cot or bassinet
• Make sure the mattress is clean, dry and fits snugly
• Make sure baby's face is well clear of bedclothes
• Place cot in same room as parents' bed
• Put baby down to sleep on their back
Source: Plunket