Senior Constable Felicity Beckett of Kerikeri police said the driver of a ute had pulled over on to the shoulder after missing a turn-off. He checked his mirrors before starting a U-turn, but failed to see the approaching Coastguard ute and the two vehicles collided.
Ms Beckett said drivers should always check by looking over their shoulders before attempting a U-turn.
"You can't be dependent on mirrors alone. There's too many blindspots in these vehicles with their wide pillars. You have to look again and again and again," she said.
She also reminded motorists they were required to reduce speed to 20km/h while passing an accident scene. Few were observing that rule on Sunday afternoon, she said. No one was injured in the crash, which partly closed SH10 while the boat was hoisted on to a truck.
Whangaroa Coastguard president Bob Kidd said he hoped to have the boat in the water and ready to respond to emergencies by Sunday evening. It was not damaged but its pontoons had to be deflated to get it on to the truck.
The group's own boat, Whangaroa Rescue, scraped its keel during last week's search in Cable Bay. The damage was minor but the vessel had to be 100 per cent before it was put to use, he said. Police are still considering whether to lay charges in relation to the crash.