Around 50 long-finned pilot whales have become stranded on Farewell Spit.
The stranded occurred at around 9:30am yesterday morning. The Department of Conservation were alerted to the whales by a tour operator.
A spokesperson said nine of the original 49 whales had died. However, the other 40 were refloated by a team of volunteers.
A team of about 65 volunteers, Department of Conservation rangers and Project Jonah experts have been keeping the mammals cool and wet throughout the day.
At about 9.30pm, the refloated whales were swimming about 80 metres offshore from the stranding site.
Conservation staff will check the beach at first light today to see whether any have re-stranded overnight.