More than 30 sheep were killed, with many having to be euthanised, after they were attacked by two dogs on a South Auckland property.

Details of the attack were posted on Facebook by concerned residents, worried after noticing the dogs flee the scene on Kauri Rd, Pukekohe.

However, Sarah Anderson, manager animal management at Auckland Council, said both dogs were caught.

One was shot by a farmer, dying instantly, while the other one was currently being treated for a gunshot wound at the animal shelter.

"Animal management officers were at the scene of this attack all day yesterday. More than 30 sheep were killed as a result of the attack, with a number having to be euthanised as a result of their injuries," Anderson said.

"Late in the afternoon two dogs were shot by a farmer. One was killed instantly, while the other one was followed back to a property and impounded by an animal management officer. The dog was taken the vet, where the gunshot wound was treated.

"It is now being held at an animal shelter."

The council's investigation into the attack is continuing today.