The deaths of two newborn babies delivered at home by midwives has prompted the Wellington coroner to call for a national review of maternity services.

Coroner Garry Evans said midwives were increasingly becoming sole maternity providers and looking after more high-risk patients subject to emergencies they may not be prepared for.

The work of midwives was growing as the number of new doctors specialising in obstetrics and gynaecology fell, he said.

Mr Evans has released his findings into the deaths of babies Saskia Marama Swagerman-Fugle and Cameron Elliot following undiagnosed breech deliveries.

Saskia died at Wellington Hospital in February 2001 six days after she was born at home in Newtown suffering from severe asphyxia and brain damage caused by her umbilical cord being compressed during birth.

Cameron died at home in Peka Peka Beach, on the Kapiti Coast, in April 2003 after suffering spinal damage and asphyxia caused by his head taking 11 minutes to deliver. In both cases the lead care midwife failed to conduct a vaginal examination.

Expert evidence found Cameron's death was "preventable" and it was likely Saskia's birth "would have had a better outcome" if the breech delivery had been diagnosed earlier.

The coroner has recommended the Health Minister launch an independent review of the Maternity Services Scheme and carry out a national audit of the deaths of babies cared for by public maternity services and independent midwives.

Midwifery education and training should also be reviewed and, following graduation, midwives should be required to serve a 12-month internship in a public hospital before going into private practice, Mr Evans said. New graduates should also be supervised by an approved practitioner for at least a year. Guidelines for resuscitating newborns should be reviewed and, along with the importance of vaginal examinations, be re-emphasised in midwifery training, he said.

But the New Zealand College of Midwives said many of Mr Evans' concerns about midwifery were unfounded. "The coroner has overstepped his brief into matters where he did not give the profession or the maternity services in general an opportunity to offer evidence on the state of current practice and services," said college chief executive Karen Guilliland.

"There is no evidence to support the coroner's extensive and disruptive recommendations."

There was no evidence outcomes were deteriorating, Mrs Guilliland said.

"The overall infant death rate has decreased by over 25 per cent over the last 15 years and continues to decline ... "

The Midwifery Council and the college already required midwives to participate in continuing education and lead carers reviewed their practices before a panel every year, Mrs Guilliland said.

The deaths of Saskia and Cameron were tragic and should be scrutinised for lessons to be learned.