New Zealand veterinarians have performed world-first brain surgery to save the life of a critically endangered native parrot chick.

Key points: There are only 144 of the flightless and nocturnal kakapo left in existence, making the surgery important

There are only 144 of the flightless and nocturnal kakapo left in existence, making the surgery important An abnormal growth was discovered in the chick's skull shortly after it hatched

An abnormal growth was discovered in the chick's skull shortly after it hatched The veterinary surgeons had no precedent in the avian world, so adapted techniques used on humans and other mammals

The chick, known as Espy 1B, was discovered to have an unusual lump on its skull shortly after hatching at a NZ Government-run conservation centre on Codfish Island, an island off the country's southern tip.

There are only 144 kakapos left in existence, making the efforts to save the chick even more important.

The chick was flown for free by Air New Zealand to Massey University's Wildbase Hospital in Palmerston North where the vets took scans to identify the problem.

The surgery to repair the developmental problem had never been attempted in avian medicine. ( Supplied: Massey University )

"The chick was hatched with a hole in its skull that allowed part of the brain and dura [the tough barrier around the brain] to herniate out," said Brett Gartrell, who led the team which performed the surgery.

"In humans, this spot fuses after birth, but this is highly unusual in birds as the skull has finished fusing prior to hatch. The concern was that if this tissue was damaged this would open the brain to trauma and infection.

"With only 144 kakapo left in the world, this condition could be life-threatening for the critically endangered bird, so action needed to be taken, but nothing like it had been attempted before in avian medicine."

The chick Espy 1B will be taken to a wildlife hospital in Dunedin where it will be paired with another chick. ( Supplied: Massey University )

Professor Gartrell said with no precedent available, they took inspiration from surgical procedures in human medicine.

"This is a risky surgery and the common complications for this surgery in humans and other mammals include permanent brain damage, continued leakage of cerebrospinal fluid and the possibility of meningitis," he said.

The university said the chick has recovered from the surgery and is now healthy and it will be transferred to a wildlife hospital in Dunedin, where it will be paired with another chick to minimise its contact with humans.

The kakapo is a flightless, nocturnal bird whose existence has been threatened by introduced species.

The majority of the remaining population lives on two islands which have been cleared of predators.