MELBOURNE - Australian doctors successfully separated Bangladeshi twins who were joined at the head after more than 24 hours of surgery on Tuesday, describing the moment as "surreal".

Neurosurgeons who worked through the night finally divided the brains of Krishna and Trishna, two, at about 11:00 am (0000 GMT), chief of surgery Leo Donnan told reporters, adding both girls were well.

"The moment of separation was a rather surreal moment. There was relief but I think everyone realised there was still a long way to go and that the girls have a very difficult time ahead of them," Donnan said.

Plastic surgeons will now close their skulls with bone and skin tissue to prevent infection, with the girls expected to remain in an induced coma for several days.

The girls were close to death when they were rescued from a Dhaka orphanage two years ago, and doctors gave the highly complex operation just a one in four chance of complete success.

Donnan said the 16-strong team, which took regular food and rest breaks and listened to pop music in the operating theatre to stay alert, was elated to see the girls separated.

"It's something which for two years has been planned," he said. "Everyone has known these girls as one with their individual personalities, so to see them as separate human beings is a pretty amazing moment."