Women who give birth in public hospitals are also more than twice as likely to suffer tearing, or their babies will need resuscitation, according to the findings of a study.

Associate Professor Steve Robson and colleagues examined the outcomes of almost 790,000 births which took place over four years, and about a third were in the nation's private hospitals. Dr Robson said he was shocked not only by the ''striking difference'' between the two systems, but also by the results that contradicted a common criticism of births in private hospitals. ''There is often a lot of criticism in the medical press of rates of caesarean birth and rates of the induction of labour everybody says, 'Wow, they're so much higher in private hospitals','' Dr Robson, of the Australian National University Medical School, said.

''And if you take the literature at face value, all of those things ought to up the complication rate, [but] it was lower.

''We found that quite staggering.'' Dr Robson says the study raises questions about the view some in the medicine hold that ''increased rates of obstetric intervention are bad for women and their babies''.

''Our study suggests these things could be beneficial because the rate of babies dying is about half in the private hospital, and the rate of serious maternal injury is less than half,'' he said.

Dr Robson said differences in the health and socio-economic status of the mothers alone could not explain the performance gap between public and private hospitals, and that further research was needed.

''And it's not as though we've taken a small sample, we basically looked at every birth in the country [over four years]'' he said.

The study, to be published in the Medical Journal of Australia, reported women giving birth in public hospitals had more than twice the rate of ''severe perineal tearing'', and their babies were more than twice as likely to require ''high-level resuscitation'' at birth.

The neonatal death rate was one for every 1000 babies born in private hospitals, compared with three in 1000 in public hospitals. The study was also undertaken by Elizabeth Sullivan and Paula Laws, of the Perinatal and Reproductive Epidemiology Research Unit at the University of NSW.

Australia's rate of caesarean sections has risen from a single digit per cent in the 1980s to now account for more than 30 per cent of all births.