SYDNEY (Reuters) - Conjoined Bhutanese sisters were separated in a six-hour operation at an Australian hospital on Friday and the lead surgeon said he was quietly confident the infants would recover successfully.

The 15-month-old twins, Nima and Dawa, were joined from the chest to the pelvis. Doctors at the Royal Children’s’ Hospital Melbourne (RCHM) said they had to separate the girls’ livers, and the main challenge was reconstructing their abdomens.

“It is a relief and it is also a joy, there’s nothing better in any operation to be able to go to the parents and say we have been able to take care of your child,” Dr. Joe Crameri, who led the 18-strong surgical team and is the head of pediatric surgery at the hospital, told a media conference.

“There will be challenges over the next 24 to 48 hours as with any surgery, and we feel quietly confident that we will have a good result,” said Crameri.

The girls and their mother, Bhumchu Zangmo, were brought to Australia last month by the Children’s First Foundation charity, which said the Victorian state government had covered the cost of the surgery while it looked after transport and accommodation.

When they arrived, the medical team said the girls needed to improve their weight and health before surgery. The girls are expected to remain in hospital for at least a week, Crameri said.

In 2009, doctors at RCHM successfully separated conjoined Bangladeshi twins, Trishna and Krishna in a 25-hour surgery.