Northland's harbourmaster is threatening to make Whangarei's harbour channel a no-anchorage zone after a series of near misses involving small recreational boats crossing the path of large ships.
Regional harbour master Ian Niblock  said it was only a matter of time before a small boat was run over. It was happening more than once a week.
He said more than 90 per cent of small recreational boats were taking unnecessary risks in the channel.
"We at the council, in consultation with port operators and pilots, are at the point of saying either improvements are made or the whole harbour channel will be declared a no anchorage area," Mr Niblock said.
He said legislation, rules and bylaws required vessels weighing less than 500 tons to get out of the way of bigger vessels.
"Large ships do not have a lot of clearance under or on  sides and a lot of times, they travel at a certain speed and set course and therefore, they have very limited capacity to avoid collision with small boats.
"Crew on board large vessels lose sight of what's in front and if a small boat breaks down while crossing in front of large vessels, it will be run over."
Small boat operators sometimes anchored inside the channel and on occasions refused to get out of the way, he said. He blamed the problem on a lack of knowledge and poor seamanship.
"At the end of the day, safety has to be the primary driver," he said.
Outboard Boating Club of Northland administrator Bill Bell supported the council's approach, saying people should use their common sense and steer clear of large vessels. He hoped the club's 800 members were aware of the issue.
Mr Bell said even the council's brochure titled Northland Harbour Guide advised small boat operators to give way to large vessels not able to change course in narrow channels.
He said the brochure also talked about the need for small boaties not to anchor in the channels. "I do see small boats anchored there and it's dangerous. If the council wants to put down something in writing, so be it," he said.