Coroner Ian Smith says parents are putting their children's lives at risk if they ignore ongoing warnings about unsafe sleeping arrangements.
Mr Smith investigated the death of Illusion Namana-Wiwarena who died from Sudden Unexpected Death in Infants, previously known as cot death, in September 2010.
Illusion was a week old when he died while sharing a double, pull-out sofa bed with his parents and a two-year-old sibling.
Mr Smith said it is another tragic loss from an unsafe sleeping environment, coupled with a baby sleeping with others.
He said the death is in spite of continual warnings from health advisors about bed sharing.