Sydney  - Joined-at-the-head Bangladeshi twins Krishna and Trishna were separated Tuesday in a Melbourne hospital.

Doctors at the Royal Children's Hospital had estimated the chances of both 2-year-old girls surviving the 27-hour operation at 25 per cent.

"To see them as separate human beings is pretty special," head of surgery Leo Donnan said. "This is a once-in-a-lifetime operation that teams would do."

He warned against declaring the procedure a complete success.

"There really still is a long way to go," Donnan told reporters outside the hospital. "The girls have a very difficult time ahead of them."

Cosmetic surgeons are at work on the twins, who will remain unconscious for several days. (dpa)