CAPE TOWN (Reuters) - A South African lion called Brutus who fathered three "miracle" cubs despite having had a vasectomy in his youth is going back to the vet to have the operation a second time.

Brutus and his partner Nala, who live at the Drakenstein Lion Park near Cape Town, stunned staff at the sanctuary when she gave birth to the cubs just before Christmas.

"We are a non-breeding sanctuary and Brutus before he became sexually mature had a vasectomy which we assumed worked because for the last three years there has been no offspring," the park's owner Paul Hart told Reuters by phone on Tuesday (Dec 29).

"So we were taken completely by surprise by the cubs."

Local media reports jokingly referred to a "Christmas Miracle" or "White Christmas" as the animals are rare white lions - an unusual genetic mutation.

Mother and cubs, who have yet to be named, are doing fine, while Brutus has a date with a vet. "Hopefully, this time round, we'll fix the problem," Hart said.

The Drakenstein Lion Park is a private sanctuary that rescues captive lions from abusive environments that cannot be released into the wild.