Australian zoo keepers were keeping a round-the-clock vigil for "Mr. Shuffles", the miracle elephant calf who survived a marathon nine-day labour despite being declared dead.

Staff at Taronga Zoo said the baby elephant, nicknamed for his unsteady gait, was growing stronger and feeding himself but cautioned he was "not out of the woods yet".

"This little calf has been through a incredibly tough time," zoo director Cameron Kerr told reporters Thursday.

"There is no record anywhere else in the world -- of the 10,000 births, there is no recording -- of a labour that has gone this long.

"There is no recording of a calf being absolutely still for several days like this."

The zoo announced Mr. Shuffles had died on Monday after a week of on-off labour. But the baby animal incredibly raised his head after apparently being stillborn on Wednesday.

"I was kind of happy she had at least expelled the calf," said senior elephant keeper Katharina Theodore.

"And then, mind-blowingly enough, the calf raised its head. We were saying, 'it's a live calf, it's a calf'."

Mr. Shuffles and his mother, Porntip, are receiving 24-hour care in a heated barn and will remain out of public sight.