Orca swimming in Pukerua Bay are causing traffic chaos as drivers pull over to watch.
The pod of orca are visible from Centennial Highway between Pukerua Bay and Paekakariki, police said.
"There have been numerous accidents reported as drivers look at the orca and not the vehicles stopped in front of them," senior sergeant Marc Clausen said.
Some motorists were parking on the side of the road and running across to get a better view, he said.
"Roading contractors are enroute to the area and will be setting up road cones to prevent people from stopping in dangerous areas."
Mr Clausen said traffic was moving slowly and drivers were urged to focus their attention on the road and not the orca.
"Police now have several patrols in the area and will be taking positive action on those motorists parking dangerously or illegally."