A lamb with seven legs was born in New Zealand but so badly deformed that it was to be destroyed, a local newspaper reported.

The lamb was born with an extra set of front legs and three back legs, the Ashburton Guardian newspaper, at Ashburton on the South Island, reported.

©Susan Sandys/AP
The seven-legged lamb rests on its farm at Methven near Christchurch on the South Island of New Zealand on Tuesday.

Farmer Dave Callaghan found the lamb in his field. Two of its legs hung useless behind the forelegs. The lamb walked using its two forelegs and three healthy hind legs.

"I have never seen anything like that," he said.

Veterinarian Steve Williams said the lamb was also hermaphrodite, and was missing a part of its bowel so was unable to pass feces.

He said it was this latter problem, rather than the fact it had seven legs, that meant it would have to be destroyed.

"It's quite a happy bright wee lamb, he's just slowly going downhill really," Williams said. "To keep it alive is probably inhumane really."

Williams said he believed an error during embryo formation had resulted in the lamb's being born polydactyl - with many legs - a condition that occurs once in several million sheep.