An Auckland skipper is concerned dozens of dead pine trees lining Motutapu Island are an accident waiting to happen.
The Department of Conservation poisoned them in 2015 to prevent them spreading, but now their skeletons haunt skipper Kevin Hester.
"There's no question about it, there's the potential for a catastrophic accident to take place," he told 1 NEWS.
Mr Hester is worried a storm will loosen the pine trees roots, and push them over the edge into the Motuihe Channel.
It is one of the busiest channels in Auckland, ferries pass through hourly to get to and from Waiheke Island, and it is also a popular spot for fishing.
"One of the big ferries going to Waiheke can hit one of those trees, lose steerage and get on the rocks before anyone could get anywhere near it."
Boats cannot get close to the cliff or the will risk hitting rocks, but the concern is fallen trees to float into the channel.
DOC told 1 NEWS the trees don't pose a risk.
"Cutting these tress down would be hazardous because of their location on a cliff above the sea," DOC told 1 NEWS.
"They're rotting from the top down and are collapsing safely to the ground."
"I'd like you to find me a botanist on the planet that will tell you those trees will rot standing and not fall over, the evidence is clear, you can see some of those trees have already come down the cliff," said Mr Hester.
Other boaties have been keeping an eye on the area too.
"It's already a piece of water where you have to concentrate and take seriously, it could be quite a major if there was a big item in the water at night when you're travelling," one boatie told 1 NEWS.
DOC says rangers will continue to monitor the trees.