Stuff.co.nz reports a dozen of the pod were found dead Monday morning after they washed up on the high-tide mark at Farewell Spit.
The Department of Conservation (DOC) made the difficult decision to euthanase the remaining 27, when it became clear an attempt to refloat them was unlikely to succeed. The location of the whales high up on the beach, low tides and strong winds would have hampered any refloat attempt.
Golden Bay conservation services manager John Mason: "We carefully weighed up the likelihood of being able to refloat them and get them safely back out to sea, but our staff, who have extensive experience in dealing with mass whale strandings in Golden Bay, determined that due to various factors it was unlikely they could be rescued."
Whale conservation charity Project Jonah reported the stranding on its Facebook page with the reminder that NZ is in peak stranding season and for 'whale medics' to have their strand bags ready to go.
NZ's stranding season is from November to March, and they're an almost annual occurrence at Farewell Spit.
Nov.2012: 28 whales died after stranding in the area.
Jan.2012: 99 whales stranded themselves at the spit - despite refloating efforts, 40 had to be euthanased.