A section of the Te Araroa Trail, which spans the length of the country, has been closed indefinitely.
Whangarei District Council parks technical officer Stuart Jackson said one of the piles of a footbridge at Whananaki had been hit and damaged by a boat.
The footbridge links north and south Whananaki, and is part of the 3000km Te Araroa Trail, which stretches from Cape Reinga to Bluff.
Mr Jackson said there were possible but unpopular options for those on the trail.
"The options for walkers are either to walk around, and it would probably be a 5 or 6km detour, or wade - but you would have to wait until low tide and wade up to one's chest level."
Mr Jackson said the bridge was at its busiest with holidaymakers and walkers at this time of year.