A diver has been rushed to hospital with an injury to his lower leg after being attacked by a stingray.
A police spokeswoman confirmed police were responding to the reported attack.
The incident was initially believed to have involved a shark, but a lifeguard at Riversdale had since told the Wairarapa Times-Age it involved a stingray.
Officers rushed to the scene following a call shortly after 1pm.
The beach was initially closed by Riversdale lifeguards amid fears of a shark attack.
However Dave Rose from the Riversdale Surf Lifesaving Club had since confirmed to the Wairarapa Times-Age there was "absolutely no shark attack".
The injured man was in a "comfortable position", he said, and was being treated by paramedics from Wellington Free Ambulance and Life Flight's Rescue Helicopter at the scene.
A Westpac Rescue Helicopter was also at the scene.
The patient has been taken to Wellington Hospital with a moderate injury to his lower leg. He is in the emergency department in a stable condition.
The beach had also been reopened and lifeguards were back on patrol.
Several months ago a commercial fisherman was lanced by a stingray in Whangarei while trying to save it, by flicking it overboard.
Dan Alders was lifting it up by its gill when its barb shot through his elbow.
As blood poured from the puncture wound, his quick-thinking skipper grabbed some towels to stem the bleeding.
"It's their natural instinct to flick their tail up," Alders said. "I'm always aware of it. I'd already thrown 30 or so over that day."
Coastguard was called to the boat that was at the Hen and Chicken Islands, off the coast of Whangarei around 10.20am due to the "severe laceration".
The Coastguard team transported Alders back to Marsden Cove, to a waiting ambulance.
Alders said he was glad he was still around to tell the tale.