The conjoined twin girls from Bhutan who arrived in Melbourne this week have undergone scans to assess their health but doctors will not speculate on when the surgery will take place.
Australian doctors are optimistic that conjoined Bhutanese Niwa and Dawa will be successfully separated, but have not set a date for their surgery.
"They're pretty small, they're fragile and we'll be taking the best care we can," lead anaesthetist, Dr Ian McKenzie said at a media conference Thursday.
"We expect it should go very well."
MRI scans taken at the Royal Children's Hospital in Melbourne have shown surgeons what organs the 14-month-old girls share, providing a clearer picture of the safest time to operate.
"We didn't see the connection was broader or bigger than we'd been led to believe," head of paediatric surgery, Dr Joe Crameri said.
"I guess I was reassured that the twins were active and interacting with one another."
The girls also underwent including blood and general health tests.
"There's a whole lot of things they might have got in Bhutan they wouldn't get in Australia, and we need to just have our guard up that they haven't got a surprise illness we haven't thought of, that might not be very common here," said Dr McKenzie.
The planned separation procedure at the Royal Children's Hospital will include splitting the girls' shared liver.
Doctors expect to have a better idea next week on whether and when surgery, estimated to take up to eight hours, can proceed.
"We need a little bit of time to put this together, but we would like to be able to meet next week with the opportunity to say we've got a plan," Dr Crameri said.
As the medical team work on their surgical plan, Niwa and Dawa's mother is becoming more anxious.
"In general, they are happy healthy girls who are interacting quite well," he said.
"So far, everything is going along the pathway that we've been hoping for."
"Mum would obviously, and has expressed, that she would like this to happen soon, so the girls can get on, in her mind, a normal life and hopefully get home."
The Victorian government said it will fully fund the quarter of a million dollar procedure.
If the surgery goes ahead and is successful, it will be months before the girls are well enough to travel home to Bhutan.
- with AAP