A University of Adelaide team has found further evidence to suggest genetics plays a bigger role than previously thought in cerebral palsy.

Up to 45 per cent of all cases of cerebral palsy in children can be attributed to genetic causes, rather than brain damage at birth, Australian researchers say.

The findings of the team from the University of Adelaide builds on other research released earlier this year indicating at least 14 per cent of cases were likely to be caused by genetic mutation.

They are now calling for an end to "unnecessary" caesareans and "arbitrary" litigations by parents against obstetric staff.

"For many years it was assumed, without good evidence, cerebral palsy was caused by brain damage at birth through a lack of oxygen," research leader Professor Alastair MacLennan said in a statement on Tuesday.

"This belief along with the temptation to blame the insured and the high cost of caring for children with cerebral palsy has fuelled litigation."

Some $300 million is paid out on cerebral palsy settlements in Australia each year.

Caesarean deliveries have increased to 34 per cent of births over the past 50 years - and Prof MacLellan believes some of that rise has been driven by defensive obstetrics.

The research, published in the American Journal of Obstetrics & Gynecology, also raises the prospect genetic testing for cerebral palsy will eventually become a reality.