A close encounter with three killer whales at Waiheke Island caused swimmers to freeze, scream - then quickly scramble out of the water.

Waiheke Island local Brett Thom said he had just arrived at the beach with his dog yesterday afternoon when he heard a scream from a woman on the beach, urging her kids to come in from the water.

Looking into the water, he said he saw two big fins.

A few children swimming in the bay seemed to freeze, Thom said, before apparently remembering they could swim.


But unwilling to swim right into shore with the orcas frolicking in the same waters, they headed to rocks in the bay and scrambled up out of the water.

Thom said it wasn't uncommon to have orca visit the area, but it was rare to have them come so close to shore.

"We don't usually see orcas come right into Enclosure Bay - you need a pretty high tide to start off with," he said.

"It's the first time I've seen them in there."

Thom said the pair of whales swam around for a short time about 30m from shore before leaving the bay.

"They came in from the east entrance and went out towards the west."

Another witness Nick Syred happened to have his drone on hand when he spotted fins coming out of the water - so sent the gadget over the bay to get a better view.

"There were three orcas, a baby and two adults," he said.

"They were teaching the baby how to catch stingrays."

After they left, Thom said the enthusiasm died down and a couple of kayakers went out to rescue the children who were sheltering on rocks.

"Everyone was quite excited at the time, naturally," Thom said.

"I wouldn't say it was a panic... or maybe I would actually. There were a lot of screams."