More than one in three babies born at the Rotunda Hospital last year were delivered by caesarean section.
The rate rose to 34.6pc - up from 28.7pc in the previous five years.
Nearly 390 patients had a C-section delivery at term before the onset of labour, the hospital's annual report revealed.
They accounted for 13pc of all caesareans and are up from 277 planned surgical deliveries in 2012.
The report said it is unclear whether these women were having a caesarean section for personal reasons or whether significant changes are happening in the medical risk profile of the patients.
A small increase has been seen in caesarean deliveries due to a possible "declining enthusiasm" on the part of patients or doctors for a trial of labour, having already had a caesarean birth.
The main drivers are the number mothers whose baby is in a breech position, with feet rather than head first. They include first-time mothers and women who have had a previous caesarean section.
The report also noted that the rise is influenced by the use of oxytocin, a drug given to speed up labour.
Changes in protocols mean staff order a caesarean section earlier if they have concerns about an unborn baby's heart rate where a woman had been administered this drug.
Other factors pushing up the rate are the increase in obesity and the number of women having repeat caesareans.
Rotunda master Prof Fergal Malone said the hospital cared for 10,024 mothers last year.
"Mothers with a healthy foetus who obtain their care in the Rotunda can be assured of a superb standard of care, better than the vast majority of mat- ernity hospitals worldwide," he said, adding that the challenge was in maintaining standards due to the hospital's outdated facilities.
The Rotunda has been earmarked to move to the campus of Connolly Hospital in Blandchardstown and the design brief is completed.
The new building is costed at about €300m, but the capital funding and timeline for the go-ahead are still unclear.
There will also be a need to provide more critical care and other services at Connolly to ensure women transferred from the Rotunda get the standard of care need instead of going to the Mater.