The Coastguard was assembled and on the water at 9.48pm.
A Coastguard spokeswoman said the waves were breaking over the top of their vessel.
There was a "massive amount of chop" making the search for the small boat, which contained two adults and two children, difficult, she said.
The crew, who searched for more than an hour, were not sure what they were going to find and remained "very focused" throughout the search, she said.
The Coastguard found the boat, brought the occupants aboard their vessel about 10.30pm. They towed the smaller boat for about 45 minutes to reach the shore.
She said the crew had all been relieved to bring them home safely and called it the "best possible outcome".
They were "a bit shaken and cold" but otherwise okay.
The group, believed to be a family, were all wearing lifejackets and used a hand-held radio onboard to alert rescuers.
The Waihi Beach Lifeguard callout co-ordinator Andrew Cochrane said it was "blowing its guts out" there today and yesterday was no different.
The conditions had been rough the further out the lifeguards went and they contacted the Coastguard, he said.