It took paramedics five minutes to restart the heart of a Taronga Zoo worker after she was pinned against a bollard by a young male elephant who shot to fame as Mr Shuffles.
Zookeeper Lucy Melo is in a critical but stable condition in Royal North Shore Hospital after the incident this morning.
Zoo director Cameron Kerr this afternoon told media the accident occurred about 11.30am during a training exercise in which the young elephants learn to wash themselves.
Mr Kerr said 2½-year-old Asian elephant Pathi Harn pushed Ms Melo against a fence pole in the barn area of the elephant enclosure.
Two other keepers heard Ms Melo call out, moved the elephant away and immediately called an ambulance.
"Our keepers did act immediately. When they saw the incident was going on they moved the elephant calf away from the keeper that was injured and called the ambulance service immediately," Mr Kerr said.
Elephant keeper Lucy Melo pictured in the elephant enclosure at Taronga Zoo in 2008. Photo: Kate Geraghty
"The elephant pinned her up against one of the fence poles, the bollards, and they came in and moved the animal away."
It took five minutes for paramedics to get Ms Melo's heart beating after she suffered a serious chest injury from being crushed, Ambulance Service of NSW acting Inspector Andrew Wood said.
Mr Kerr said some members of the public were likely to have seen the accident. He said the zoo had launched an investigation, but it was so far unclear why the animal had set upon the keeper.
WorkCover NSW is also investigating.
Mr Kerr admitted that working with large animals carried inherent risks but said there had been no risk to the public at any time.
"Our elephants are in the paddocks; they're calm and comfortable. I can ensure you that Taronga's elephant programs are world standard," he said.
Pathi Harn garnered national attention in March 2010, when he was born despite being declared dead in the womb by vets during an eight-day labour.
He was nicknamed Mr Shuffles because of his early walking attempts - like an old man shuffling around in ill-fitting slippers - before he was officially named.
Pathi Harn, which means "miracle" in Thai, was the second Asian elephant calf to be born at Taronga Zoo.
The Taronga website tells how his mother, Porntip, also a Taronga elephant, was in labour for eight days during which it was discovered through ultrasound technology that Pathi Harn was upside down making it impossible for him to proceed down the birth canal. This had never been witnessed or recorded before.
Towards the end of the protracted labour no signs of life from Pathi Harn were detected leading reproductive experts to conclude he had died in the womb.
However, on March 10, 2010, Porntip managed to turn Pathi Harn into a birthing position and against all odds give birth to him.
For the first 24 hours he was very fragile and required a lot of help and therapy from keepers in assisting him to walk and suckle.
Taronga Zoo keeps eight Asian elephants, five females and three males.
Pathi Harn was 506 kilograms on his first birthday, 18 months ago.
A fully grown male Asian elephant can weigh more than 5000 kilograms.
- with Amy McNeilage and Peter Munro