Fifteen children and an adult were rescued from a rip at Riversdale beach, east of Masterton, on Wednesday.
Peter Taylor from the Riversdale Surfing Life Saving Club told Summer Report a strong current dragged the group towards a rip which was taking them out to sea, and the swimmers were beginning to panic.
The alert was raised by an off-duty guard who'd been swimming between the flags.
Mr Taylor says tube-swimmers kept the children and adult afloat while the boats arrived to ferry them back to shore. It took about five minutes to get everyone out.
One person had to be taken to hospital, however five others who collapsed on the beach were in a stable condition by the time the ambulance arrived, he says.