The girls are joined at the torso and share a liver and possibly a bowel, their doctor said, adding "our challenge will be to reconstruct their abdominal walls to close it over", the BBC reported.
He said they would separate the liver, but there was one "unknown" --whether the girls shared a bowel. If it was, it would also be divided, he said.
However, it was postponed so the girls could improve their nutrition. Doctors said they were confident the twins were now ready for the operation.
Zangmo would spend the day praying and meditating, she added.
The state of Victoria has offered to cover the $255,000 cost of the operation.
Conjoined twins are very rare -- it is thought one in every 200,000 births -- and around 40-60 per cent of these births are delivered stillborn.
Only a few separations are carried out around the world each year.
In 2009, the same hospital performed a successful operation to separate Bangladeshi conjoined twins -- Trishna and Krishna, who were joined at the head. They underwent a life-saving 32-hour long surgery.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)