The Health and Disability Commissioner has referred a midwife to the Director of Proceedings after a four-day-old baby had to have an urgent operation.
The incident occurred in 2010 and involved a 25-year-old mother and baby, her first child.
They were discharged on a Saturday, two days after the birth, but when the midwife visited on the Monday, the baby appeared yellow and unwell.
By the following day the infant was lethargic, not feeding and and had a weight loss of 10% since being born.
An investigation found that the midwife had not discussed giving vitamin K, which helps blood to clot, with the mother during her antenatal care.
The baby was operated on in a paediatric intensive care unit.
The commissioner says the vitamin K failure, along with several other important checks, breached the Code of Health and Disability Services' consumer rights.
The Director of Proceedings is a lawyer appointed under the Health and Disability Commissioner Act. They will review the case to decide if further action is needed.