Hundreds of locals and conservation officers have been trying to rescue the survivors since early Friday and formed a human chain to refloat the whales.
Scientists do not know what exactly causes whales to beach themselves.
But it sometimes happens because the whales are old and sick, injured, or make navigational errors particularly along gentle sloping beaches.
Sometimes when one whale is beached, it will send out a distress signal attracting other members of its pod, who then also get stranded by a receding tide.
Are whales attempting suicide when they strand themselves?
The conservation department said it had received a report about a possible stranding on Thursday night, but did not launch the rescue operation until Friday morning as it was too dangerous to attempt a rescue in the dark, reported the New Zealand Herald.Source: BBC