The weaker of two conjoined twins separated in a landmark surgery in Australia has woken up from a coma — and blown a raspberry at her guardian.

"I'm smiling today and it's the only smile I've had in a week," the twins' guardian Moira Kelly said.

"I'm grinning," she said. "Krishna's woken up, unbelievable. She is neurologically sound, which gives me shivers down my spine."

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 percent perfect" after waking up on Thursday.

The team of specialists worked for 32 hours on Monday and Tuesday to divide the girls' connected skulls, brains and blood vessels in a procedure that took two years of planning and preparatory operations.

The risky surgery was initially given only a 25 percent chance of complete success.

"We've got challenges ahead of us, the children are in intensive care, they'll be there for a while and they've certainly got rehab to do," Kelly said.

"The girls are alive and they're normal. Miracle is such a wonderful, beautiful word. But it's not big enough."

Trishna and Krishna were rescued from an orphanage in the Bangladeshi capital Dhaka.

The aid worker who helped take the children to Australia two years ago, Danielle Noble, said seeing them for the first time in their newly-separated state was the "most incredible feeling".

"Two years ago this was just a dream. They look amazing," Noble said.

"I can't describe the emotion of it, of walking in there and seeing two beautiful little girls in two beds."

The twins' impoverished mother said she is overjoyed at the news the twins are doing well, but doesn't want them back.

Lovely Mallick, 22, said she gave Trishna and Krishna up soon after their birth because there was no way she and her husband could care for them.

"I'm overjoyed with the news that my babies are in good condition," she said.

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