Mr Kortens lent his binoculars to German tourists and they had a look too.
"They were quite impressed they hadn't gone into the water."
Mr Kortens was a regular beach-goer and would often enter the surf. Today, however, he'd stay out, he said.
Kapiti Heliworx chief executive Dennis Young, who spotted the sharks earlier in the afternoon, said what alerted him to the sharks was a sand trail.
"They were in so close they were kicking up sand with their tails. We could see this long, dirty sand trail and right at the end of the sand trail is where the shark was."
He thinks the sharks were bronze whalers, about two to three metres long. They were between 50 and 75m off the shore and possibly looking for stingrays, which had been plentiful in the area.
Mr Young landed his chopper on the beach and got two groups of two swimmers out of the water.
"We landed and gave them a bit of a heads up of what's going on."
One swimmer didn't understand English, but knew what "shark" meant.
"The look on their faces was quite priceless really."
Mr Young has flown in the area for a few years but never seen sharks before. He had previously spotted whales, and only this morning saw dolphins.
The Sand Castle motel is on Waikanae's beach front and owners Des and Narie Geffney and heard Mr Young's helicopter come in to land.
"We wondered what it was," Mr Geffney said.
Swimmers stay on the shore after five sharks were spotted. Photo / Mark Mitchell
"We could hear him hastily coming in to see what was what. We could just hear it in our lounge."
He and his wife didn't see the sharks.
Amy Edwards took her 11-year-old daughter and two other children, 10 and 8, to Peka Peka for a swim this afternoon, only to be told by another beach-goer there were sharks in the area.
"I'm grateful they told us. I was going to send the kids out into the water and let them go for it."
Mr Duffy said they'd been known to become aggressive toward spear fishers from time to time.
It wasn't unusual to see them in shallow water and they're often found in water less than a metre deep.
Occasionally they'd made their way to Wellington Harbour and Tasman Bay, across the straight.
Marko and blue sharks would spend time in the area, around Kapiti Island.
Blue sharks sometimes made their way into shallow water too Mr Duffy said.
According to Te Ara Encyclopedia of New Zealand, there were 11 fatal and 37 non-fatal shark attacks in New Zealand to 2014,
Since a death in 1976 at Te Kaha, the only fatal attack was in 2013 at Muriwai on Auckland's west coast where Adam Strange, 46, was killed by what's believed to have been a great white shark.
