Seventy-four whales are stranded across two kilometres on the remote beach north of Kaitaia.
So far nine have been successfully refloated. There are up to 50 whales just off-shore.
When DOC were called at 11am, 32 whales were reported stranded. By the time DOC arrived 43 whales were dead.
"It started off with not many and the number has grown as the day has gone on," spokeperson Sue Campbell said.
"At the moment we're trying to get enough people to help."
DOC staff from around Northland and Auckland are heading to the remote bay north of Kaitaia, and will be joined from volunteers from Project Jonah, Far North Whale Rescue and members of the Te Hapua community.
DOC Kaitaia area manager Jonathan Maxwell urged people to help, particularly if they have experience. They must have a wetsuit, warm clothing, and wet weather gear.
"Also if you are planning to stay overnight, you will need to be able to sleep in your vehicle, or bring a tent," he added.
Heavy sea conditions, high winds and the sheer manpower required to save such a large number of stranded mammals are factors faced by DOC as they tackle the strandings.
"We are absolutely committed to saving as many of these animals as possible, but as is always the case, human safety is the number one priority. "That's why careful and thorough planning and coordination for this operation are absolutely crucial," Mr Maxwell explained.
Ms Campbell said whale strandings in the area are not uncommon, but the number stranded today was unprecedented.
In August, a pod of 58 pilot whales became stranded at Karikari beach.
Upon discovery, 43 were already dead. A further six died during the rescue attempt, with nine successfully refloated.