A new trial to make beach swimming safer has got the go-ahead.
Rips are one of the biggest dangers on New Zealand's coastline, with seven people drowning after being caught in them in 2015 alone.
Every year, lifeguards do 1200 rescues on average, and about 85 percent of those are the result of rips.
Now, Surf Life Saving New Zealand (SLNZ), with software company Emsisoft, are using GPS data and drones to map rip currents and behavior.
SLNZ lifesaving services and education manager Allan Mundy told RNZ's Jesse Mulligan very little was known about the dangerous currents.
"And that is why we're so keen to get Emsisoft on board with the funding to allow us to get some gear into those rips and get a look at the anatomy of them."
One of the things they wanted to find out was how powerful rips were when the surf was small, he said.
"What catches [people] is when there is half-a-metre [swells] and an outgoing tide.
"And we can have a rip heading out to sea, really powerful, stronger than a lot of our lifeguards can swim, and people just aren't aware of that.
"So we hope to be able to get some good hard evidence to bring to the public to say 'even on what seemingly is a quiet day, those rips are really dangerous'."