There are fears eight whales refloated after stranding on Farewell Spit may beach themselves again.
Thirteen whales stranded yesterday. DOC said this morning five had died, one yesterday afternoon and four overnight.
The surviving eight whales were refloated by DOC rangers and volunteers earlier today, DOC said.
However there is concern the whales could re-strand in the outgoing tide.
DOC said if it looked like the whales could turn towards the shore, rescuers would try to shepherd them into deeper water.
DOC staff lost sight of the other 55 whales in the pod that were still at sea yesterday, due to choppy conditions.
Volunteers and DOC staff worked all day to keep the stranded whales wet and upright as they waited for high tide about 9pm.
The whales were located about 7km along the eastern side of Farewell Spit.
Strong winds chilled the volunteers yesterday as they worked to care for the whales.
Many were holidaymakers visiting Farewell Spit, who were recruited to help with the early stages of the rescue.
Anze Slivnik and Tina Pirh, from Slovenia, said they were out walking when a girl asked them to help.
Hank Oudhoff, from Invercargill, who was taking care of a large whale with his family, said helping the whales was an amazing experience.
"They know you're helping them."
He said the cold wind wasn't affecting them, as they were from the Deep South and used to "minus two".
Oldest son Kirk Oudhoff said it was a "bit of a change from rearing cattle". Youngest son Travis Oudhoff said saving the whales felt "awesome".
Jessie Langdon, who was visiting from Waikato, spent the afternoon keeping seawater in a pool for cooling the whales as the tide crept out.