Police confirmed a 22-year-old man had been issued an infringement notice after they received multiple reports he was riding on the roof of the taxi over the weekend.
Police said the van was stopped on Saturday night and a man was located on the roof of the vehicle.
At the time Kumar was spoken to "at length" by officers, and Police said the 22-year-old was issued with an infringement notice for riding on a vehicle in a dangerous position.
Kumar said realising what had happened "wasn't a shock, it was a heart attack", and it took him days to recover.
"When I told my missus, I can tell you, for two days we were thinking poor guy can you imagine if he actually fell off the roof and someone actually run him over."
Kumar said while it's a busy period and people want to have fun, they have to take time to look after their own safety and the safety of others.
One local, who didn't want to be named, told the Herald there had been some "piss-poor" behaviour at Waiheke Island.
"You imagine 6.30 on a nice summers day, picking people up pickled.
"It's bad for us, because if that kid comes off the roof what happens, whose fault is it? It's bad. We have to put up with that sh** because we have because we have these arrogant self-entitled Auckland young kids that come over here."