Fire and Emergency New Zealand (FENZ) district manager Jeff Maunder said some of the firefighters who responded to the "tragic" crash were "sadly" related to the victims.
"We express our heartfelt sympathies to everyone who was affected by this terrible event."
Yesterday, Maunder said the organisation would continue to support the crew involved in the incident.
"Tragedies in small towns like this hit home for the entire community," he said.
"We thank everyone who has rallied around the family for support."
Whakatāne deputy mayor and Tāneatua Community Board councillor, Andrew Iles, said the crash was an "absolute tragedy" and he was in "total disbelief" when he heard the news.
There had been a mood shift in the township, he said.
He said the loss of all the occupants of one car would impact the "very local" families who he understood to be from the Tāneatua and Ruatoki area.
Iles understood those in the other car were from the Waimana township - about 13km away.
Tāneatua Community Board deputy chairwoman Toni Boynton said the family was well known in the township and the wider Whakatāne district.
Tāneatua had a population of about 5000 and Boynton said everyone was connected to each other in some way, and everyone would mourn this loss.
"Our sincere aroha, sympathies, and condolences go out to the family."
Whakatāne mayor Judy Turner said it was an "incredibly sad tragedy" for the Tāneatua and Waimana communities.
"Everyone is impacted," she said of the close rural communities.
"I extend my heartfelt sympathy to them all."
