A pod of stranded pilot whales swam away on the overnight high tide near Farewell Spit.
The pilot whales beached themselves at Puponga Point at the top of the South Island at about 2pm on Friday.
The Department of Conservation says the mammals could be heard milling around and communicating with each other when the tide came up at midnight. By 1am, they had swum off.
DoC is now looking for them. It fears they are likely to become stranded again on the sandbar.
The pod has been reduced to 66. Nine died on Friday, including a baby, and a further five died overnight.
A breakaway group of pilot whales was sighted off the coast of Golden Bay on Saturday morning.
DoC says a resident at Pakawau reported seeing about 15 whales about 3km from Puponga, where Friday's stranding occurred.
DoC says one whale is stranded. Rain and low cloud has delayed an aerial scanning the area to find the rest of the pod.