Juanita the duck resting after the surgery to repair her severed beak, with the tube used to feed her.

A Wellington duck found with her beak hanging by a thread will live to quack another day after cutting-edge surgery.

The bird, now nicknamed Juanita, was found recently by staff at an Ohariu Valley bird centre run by "Duck Man" Craig Shepherd.

Shepherd runs the bird rehabilitation centre for ducks and other waterfowl, and typically rescues about 450 birds each year.

But he had never seen an injury like Juanita's, he said.

"It was quite a clean fracture, right at the back of the beak. The whole beak was intact but hanging by a strip of flesh ... It was dreadful."

The adult duck was kept in the rehab centre for four days to ensure she survived the shock of her wound. Meanwhile, Shepherd consulted his vet Alistair Ferguson, and hatched a plan to use pins to re-secure the beak.

"I'd never seen it done before, and I've been across bird 'repairs' for quite a while. It's my guess that it's a New Zealand first."

In the one-hour, $300, surgery last Thursdaythe vet cut back the beak on both sides of the break so it would meet cleanly, and then inserted pins.

"They were pushed in as far as we thought we could go without them entering the head... The pins will be there forever. [The duck] will never get through an airport scanner."

As a wild animal, Juanita would have tried to hide the pain she was in, before and after surgery, he said. "When they look wounded or sick, then they get predated on, so they pretend they're perfectly well."

But post-surgery, Juanita's appetite – and feisty spirit – had returned.

Shepherd said he knew people would think him "quacking" mad to go to so much effort for a common duck. But he said the breakthrough surgery could one day help a rare or native waterfowl in the same predicament.