Waka Kotahi NZ Transport Agency is advising motorists that an amber alert is forecast for the Auckland Harbour Bridge from 4am-7am tomorrow (Friday 19 May).
A red alert is also likely from 11am Saturday 20 May.
Under an amber alert, speeds are reduced and some lanes are closed and under a red alert all lanes on the bridge are closed.
Motorists are urged to drive to the conditions, look out for the electronic message boards which will indicate lane closures and reduced speeds, or full bridge closure, and stay within their lane while travelling across the bridge.
Drivers of high sided vehicles and motorcyclists are advised to avoid the Auckland Harbour Bridge and use the western ring route on State Highways 16 and 18.
