The larger whale stranded on Baylys Beach near Dargaville is still alive this morning, despite attempts to refloat it failing.
Rescuers on the beach this morning have reported she - experts said she is likely female - is still breathing.
The whale has been on the Northland beach for around 50 hours.
Project Jonah New Zealand general manager Daren Grover said the whale was tired and stressed, and has been calling out.
Volunteers planned to attempt to refloat her again today.
The smaller whale stranded at the same time died yesterday morning.
More to come.