The latest figures show babies born to the most deprived 20 percent of New Zealand families are five times more likely to die than those born to the wealthiest 20 percent.
The figures are included in Ministry of Health figures on fetal and infant deaths for 2011.
The infant death rate for the poorest families was 8.5 per 1000 live births, compared with 1.7 deaths per 1000 births in the richest families.
Deprivation also lifted fetal death rates.
The data also reveal that infant death rates for Maori were more than twice as high as for other groups, while the figure for Pacific Island rates was 70 percent higher.
The Tairawhiti DHB, in the Gisborne region, recorded the highest rate of infant death with 10.6 deaths per 1000 live births.
The Wairarapa DHB recorded the lowest rate.