If all goes well, conjoined Bhutanese twins Nima and Dawa will be out of hospital in time for Christmas following delicate separation surgery.
After two delays, the 15-month-old girls are scheduled for the six-hour procedure on Friday at Melbourne's Royal Children's Hospital.
"We feel reasonably confident we will be undertaking the procedure this Friday," head of paediatric surgery Joe Crameri said on Wednesday.
"Because they are getting stronger they are bickering a little bit more.
"Dawa, who is always on the bottom is trying to find a way from not being on the bottom all the time."
There is a very low chance of the surgery being cancelled as the girls are "very strong", Dr Crameri told reporters.
"We want complete separation with two girls that are then totally independent," he said.
On previous occasions, last-minute checks showed the pair were not "quite to the level we'd anticipated".
"It was the right decision not to go ahead," he noted.
The twins, who were brought to Australia with their mother in October, are joined at the torso and share a liver.
It is also possible they also share a bowel.
The girls' mum was "obviously disappointed" when previous surgery plans were cancelled.
"In a very Bhutanese way, she was very stoical about that and kept smiling," Dr Crameri said. "She is now excited."
Doctors hope the surgery will be "straightforward" but if there is an issue, the twins are in the best place to get the care they need.
The surgery is expected to involve 18 medical staff, with two teams for the girls, plus nursing and anaesthetic support teams.
The sisters have put on at least 2kg since their arrival in Melbourne, under the care of the staff at the Children First foundation retreat in regional Victoria.
Foundation chief executive Elizabeth Lodge said the girls are happy, moving around, and even singing Twinkle Twinkle Little Star.
"Very happy, very jolly, giggling, it is beautiful," she said.
"They throw toys like baseball players, they are amazing. Bring it on."
Dr Crameri hopes the girls will be out of hospital within a month of the surgery.
The procedure and recovery are expected to cost at least $350,000 and the state government has offered to pay the bill.
Other funds raised will go towards their rehabilitation and return home.
Christmas is celebrated in Bhutan, which is a mostly Buddhist nation.