Six of eight stranded pygmy whales which were rescued from the opposite coast have now been refloated at Rarawa Beach in Northland.
DoC spokeswoman Abigail Monteith said the whales were swimming about 400m offshore late this afternoon.
"Far North Whale Rescue, DOC, Project Jonah and other volunteers are continuing to monitor them, with the hope of leaving them later today.
"DoC would like to thank everyone for their hard work over the last few days in the rescue of these pygmy whales and we are hopeful that the six whales that have been refloated will remain at sea.
"Details regarding the deceased whales are being confirmed with iwi at the moment."
The pygmy killer whales - a rare type of oceanic dolphin - were discovered along a 6km stretch of Ninety Mile Beach between Te Paki Stream and The Bluff on Sunday evening.
Two had to be euthanised at the stranding site but rescuers saved the rest by turning them upright, moving them above the high-tide mark, and keeping them cool and wet.
Two of the whales transferred to Rarawa Beach this morning have also had to be euthanised.
One person at the scene said there were two shots fired and "lots of tears".
Six other whales remained in the water with a group of people about 50m out. Two IRBs from Ahipara based Far North Surf Rescue were trying to drive the whales further out.
"The matriarch came back in to shore, worrying the rescuers," the onlooker said. "She has been taken back out to the main group.
"The chances of the main group surviving now looking better."
Earlier, a Department of Conservation (DoC) spokeswoman said all eight survivng whales were successfully moved to Rarawa Beach on Monday and rested overnight in a stream.
Conservation staff and volunteers stayed with the whales overnight.
A statement from the Far North Whale Rescue group this morning said the whales would be put back in the water at the south end of Rarawa Beach from about 10am.
The group would be using a prototype drag-mat to shift the whales, still on the mats, to the sea shallows from the creek where they spent the night.
"The whales will then need to be rocked in the water from side to side for an hour or more by teams of people, to enable the whale to 'equalise' their balance so that they can swim properly once released as a group sometime around midday," the statement said.
The Department of Conservation spokeswoman said two IRB vessels were on hand, manned by surf life savers, in support.
"[The] whales will be held in a holding pattern in the water with volunteers, DOC staff and whale rescue personnel.
"Two whales at a time will be towed in pontoons out to deeper water after an hour or so of re-floating to be released."
The Far North Whale Rescue group advised any further voluteers to report to a check-In tent at the Rarawa Campground before going to the beach to help - in order to be given ID wristbands and instructions.