Boaties are being asked to take care around the Lower Hatea River Crossing as installation of fender piles and pontoons is being carried out.
A barge will be out on the water installing piles for fenders that will mark the channel, and pontoons for boats while they stop and wait for the bridge to open.
The work will take about three weeks.
Made of marine-grade treated timber, the fender piles will act as a guide through the channel for boats passing beneath the bridge.
Whangarei District Council infrastructure and services manager Simon Weston said that should a boat go off course trying to pass underneath the bridge it would be deflected by these much softer fenders rather than the concrete bridge piers.
When boats approach the bridge they will phone or radio in to the bascule operator and request the bridge to open. The pontoons will allow the boats to tie up and wait safely for the bridge to open.
Each pontoon will have two piles at each end which will be driven 5-6 metres into the river bed by the piling barge.
"A large piling barge will be on site in the main channel and additional care will need to be taken. Particular care will be required as it may get crowded in the main channel at low tide when the piling barge is working between the bridge piers," Mr Weston said.
Bridge completion is on track for July. The bridge will be closed to boats during peak-hour traffic between 7.15am and 8.45am and 4pm and 5.30pm.