Four small heads bobbing in and out of massive waves and being battered against the rocks spurred two sisters into action - despite not having any surf lifesaving equipment.
Lauren, 17, and Hannah Williams, 15, who have spent every summer at Mangawhai Beach where they are also surf lifeguards, saved a family of five from the stormy sea.
The sisters were at the beach to check out the monster waves that had been churned up by the tail of Cyclone June on Tuesday morning when they noticed the man and four small children about 50 metres from the shore moving rapidly towards the rocks at the southern end of the surf beach.
Around 10.30am, there were about 20 surfers in the water, Lauren said, and dozens of people on the beach watching, but no lifeguards on duty because the funded lifeguard season had ended.
"When I first saw them I thought 'that's something to keep an eye on', and they did look in trouble," she said.
Hannah said that as soon as she saw them approaching the rocks she ran straight in.
"I thought there were five or six of them and I knew that between the two of us we could handle it," she said.
Fear never crossed the sisters' minds, and more than a decade of dedicated surf lifesaving training kicked into gear for both of them.
Three girls, Lauren guessed they were aged from about 5 to 13, were out over their heads in the ocean struggling to stay afloat, even though two were wearing lifejackets.
Lauren grabbed the three girls and pulled them away from the rocks and swam them back to shore.
Hannah, the stronger swimmer despite being younger, went straight to the man, who was white in the face and panicking.
She told him to stay where he was while she saved the young boy, who was being beaten against the rocks with every wave that came.
"The man was in total shock," Hannah said. "But I knew I had to get the boy who was bashed by the waves on to the rocks and getting cut up."
She said another one or two waves and the boy would have been swept over the rocks and into the estuary, where the current would have taken him straight out to sea.
Hannah held on to the boy to get him away from the rocks, and told the man to hold on to her as she swam them both back in to the beach, against a very strong current.
The children were crying, and wanting to give their rescuers hugs, Lauren said, but the family quickly left the beach.
Mother Anna Williams said she is very proud of her daughters, and never feared for their safety in the massive surf.
"That is just what they do," she said.
She said she couldn't believe a man would be swimming in water of that condition with five children to look after.
This isn't the first time Hannah has been involved in a rescue while off duty.
On January 31 last year she pulled three men out of a strong rip that was dragging them out to sea.
The experience on Tuesday hadn't shaken the sisters up. They headed straight back in to the ocean for a bodysurf once the rescue was over.