Video that took the internet by storm on Tuesday of a Greymouth man smashing his jet boat into a lone pole on the Grey River was only made aware to authorities when the video went viral.
Kieran Wisdom posted the video to Facebook that has now been viewed more than 800,000 times.
An incident where he came out of it with minor injuries.
A Grey District Council spokesman says the incident happened "a while ago" but was never reported to them.
"Until yesterday morning, port staff were unaware of the incident," he says.
"Recreational vessels can enter the Grey River at any of a number of places and, because we do not have a harbourmaster, the boat club members largely have their own code of conduct."
The council says there was an arrangement between boaties of a 5-knot (9kmh) speed limit.
However it has never been enforced and has never been an issue in the past.
"[The] Council is in negotiations with other ports on the issue of regional harbourmasters each taking control over a number of Ports [in the area.]"
They say they will be in contact with the people involved in the incident.