Thirteen pilot whales that survived a stranding in the Far North on Friday were refloated on Saturday but four had to be killed when they came inshore again.
The Department of Conservation (DoC) says the whales were released at Matai Bay at 4.15 on Saturday afternoon.
It says rescuers towed a female whale out of the bay ahead of the 12 other whales, in the hope that she would lead them away from shore.
DoC says most of the whales headed out to sea but four tried to strand themselves again or displayed erratic behaviour when swimming close to shore.
It says it was concerned the distressed whales would attract the other nine back to the bay, and decided to euthanise them.
Most of the 58 whales found at Karikari beach on Friday morning died. Lifting equipment and diggers were used to get the survivors back in the water and along to Matai Bay, which is more sheltered.