The weaker of two Bangladeshi twins separated from her conjoined sister in landmark surgery in Australia woke fully from a coma yesterday - and blew her guardian a raspberry.

"I'm smiling today and it's the only smile I've had in a week, I'm grinning. Krishna's woken up, unbelievable ...and she is neurologically sound, which gives me shivers down my spine," Moira Kelly told reporters.

Kelly said she gave a "big yelp" when Krishna blew her a raspberry and there was "a bit of a sniffle down the phone" when she shared the news with the team of 16 surgeons who separated the two-year-olds.

The other twin, Trishna, was said to be "100 per cent perfect" after waking up last Thursday.

And, speaking to AFP from her home in Bangladesh, the twins' impoverished mother said she was "overjoyed" that her girls were doing well.

"No mother in the world could be as proud as me. I always knew that they would get separated," said Lovely Mallick, 22. "I just knew everything would be okay in the end for my girls.

"My babies are now in good condition. I pray that they will be fully cured soon and lead normal lives. They will be educated and smart.

"I do want to see them. I want to take care of them. I want to go to Australia."

She explained how she and her husband Kartik, 30, had given up the girls to the Nirmola Missionary Child Centre in their home town of Khulna, 135 km southwest of Dhaka.

The girls were then transferred to the Mother Teresa home in Dhaka where Australian volunteer Danielle Noble began the mission to get them to Australia.

A team of specialists worked for 32 hours last Monday and Tuesday to divide their connected skulls, brains and blood vessels in a procedure that took two years of planning and preparatory operations.