His fishing tackle and bait could be seen in the grass where he lost footing.
There was no railing at the section where the man fell, Mr Legg said.
"There was a fisherman already down there, and he went off for a wander to stretch his legs, and he found the guy. So he could have been there for a little while."
Mr Legg added: "He went off for a walk and heard him, more than saw him."
He said the chopper dropped a paramedic off and together with the ambulance staff tended to the man.
"We put him in a sling and carried him out to a point where the chopper could come and winch him off, and they took him around to what we call Waititi Bay, which you can actually see from where he fell, and got him into the back of the helicopter and away they went."
He was "a lucky man", Mr Legg said.
Despite the lack of railing and slippery nature of the path, Mr Legg said: "We don't get a lot falling over there.
"But it's one of those things where I suppose if you look out to sea or something you'd probably miss where you're supposed to go, which is easy because there's a lovely view from there."