"Just the way they looked, speaking from experience, I know the signs. I was an addict for 25 years," he said.
The man was wearing sandals, Katipa said, and he believes he must have slipped over the edge.
By the time Katipa returned from walking his dog, the man had fallen and an ambulance had arrived.
Emergency services were called to the scene around 12.42pm on Saturday, and St John Ambulance said the man was taken to Auckland Hospital in a serious condition. He was now stable, an Auckland DHB spokesperson said today.
An ADHB spokesperson said there were four synthetic cannabis-related cases admitted to hospital so far this weekend - but would not confirm if the man was one of them.
Neither St John, or police could confirm to the Herald that synthetic cannabis was a factor in the man's fall.
However, Kapita believed it was.
"It's shocking all right, what this stuff is doing to our people, to New Zealanders," Katipa said.
"I just want to make people aware that that stuff is dangerous."
There are fences and warning signs at the creek, where three children have died since 1993.