Auckland Harbour Bridge alert: Strong winds may force sudden closure

The Auckland Harbour Bridge may need to close this afternoon as powerful gusts barrel through the city.

Waka Kotahi NZ Transport Agency has triggered an Amber alert, warning motorists to expect possible lane closures and reduced speeds on the bridge before lunchtime and between 2-3pm when gales of up to 90 km/h are forecast to hit.

It is also warning it may need to shut it down to all traffic until the winds ease.

"The safety of road users is our top priority and we won't hesitate to reduce speeds, close lanes or close the bridge if necessary," said the road agency.

Those in high-sided vehicles and motorcycles are being advised to avoid the bridge altogether and instead use the western ring route. Other motorists are being urged to drive to conditions.

Waka Kotahi said it was working closely with MetService to monitor wind speeds with maintenance crews out on the network ready to react and close lanes on the bridge if wind gusts exceed threshold levels.

Motorists were advised to plan ahead by checking the Waka Kotahi Journey Planner or the Waka Kotahi Twitter account before heading out.

The agency thanked road users for their patience when it was forced to close or partially close the bridge during an extreme wind event.

Earlier this week stormy weather saw speeds reduced to 50 km/h on the city's iconic superstructure as wild winds whipped across the waterfront.

In recent months storms have seen the bridge shut at a moment's notice and high-sided vehicles, including Auckland's double-decker buses, being forced to abandon their journeys or travel on the alternate northwestern highway route.

It follows the dramatic crash of two trucks in a storm nearly two years ago that saw powerful 120 km/h gusts shunt one of the large vehicles into a key load-bearing beam, leaving the middle lanes unusable.

The freak accident left the bridge down to half its normal lanes with teams working on a fix for weeks.

The road agency asked people on the North Shore to work from home or use the Western Ring Route or buses.

Since the incident motorists have been put on notice whenever the wind reaches a threshold deemed unsafe to travel across the bridge for fear of further damage.