MELBOURNE, AUSTRALIA - Bangladeshi twins Trishna and Krishna are set to wake up 'soon", just two days after marathon surgery in Australia to separate their conjoined heads, the hospital said on Thursday.

The two-year-old girls, who have been in induced comas since the high-risk, 32-hour operation, could be awake later in the day as their sedatives are eased, a Royal Children's Hospital spokeswoman told AFP.

The girls will wake up 'at some stage soon. We don't have the exact times", she said, adding that further news would be given later.

A team of specialists worked through the night on Monday to separate the girls' skulls, brains and blood vessels before reconstructive experts closed up their heads to prevent infection.

Surgeons have given just a 25 percent chance of both twins, who were rescued from a Dhaka orphanage, making a full recovery. However, both have responded well to the notoriously difficult procedure.

'They are doing well. They are stable and are showing good vital signs,' another spokeswoman said late on Wednesday.

An emotional Moira Kelly, one of the girls' legal guardians who brought them to Australia from Bangladesh, called the events a 'miracle'.

'It's a miracle we have here at the hospital ... I can't comprehend, it's like being in the twilight zone,' a tearful Kelly said on Wednesday.