A red alert has been issued for Auckland Harbour Bridge as severe and potentially damaging winds strengthen, causing major traffic disruption.

MetService has issued a red alert for the bridge until midnight tonight ahead of strong winds that are expected to force intermittent closures of the Auckland Harbour Bridge throughout the day, with the most frequent expected between 5pm and 9pm.

The NZ Transport Agency (NZTA) posted to social media at 1.10pm saying the bridge had been closed in both directions due to severe wind gusts.

The bridge has since reopened, but with reduced speed limits. The closure lasted around ten minutes.

Earlier Sunday morning lanes were also reduced on the bridge due to strong wind gusts.

Auckland Transport (AT) noted the winds were “likely to cause short duration closures and lane reductions to the Auckland Harbour Bridge throughout the day” and advised riders check their service before they travel.

“Buses that cross the harbour bridge may be delayed, cancelled, or detoured intermittently throughout the day. Some buses may terminate their routes at either side of the bridge.”

The disruptions are expected to affect routes NX1, NX2, MEX, 866, 802, 82, 95B, 95C, 939, 923, 97R, 97B, 966, 931, and 933.

“We’ve got a big, strong southwesterly change sweeping through, and that’s where we’ve got these widespread severe gales coming from,” MetService meteorologist Silvia Martino told the Herald.

The NZTA had earlier warned it would likely close the harbour bridge for “brief periods” today.

“To ensure safety, speed limits on the bridge may be reduced, lanes on the bridge may close, or short periods of full closures may be required,” the NZTA said.

“Keeping road users safe and protecting the bridge are a priority. Decisions to lower speeds or close lanes are carefully considered.”

The transport agency said motorists needing to cross the bridge should use the western ring route on State Highways 16 and 18 instead.

MetService has issued an orange strong wind warning for Auckland, Great Barrier Island and the Coromandel Peninsula for between 3pm and midnight.

The forecaster said there was a chance it would upgrade this to a red warning, saying gusts up to 120km/h were possible in exposed areas.

“Damage to trees, powerlines and unsecured structures is possible. Driving may be difficult, especially for high-sided vehicles and motorcycles,” MetService said.

Civil Defence group Auckland Emergency Management said people should prepare by tying down outdoor furniture or trampolines, clear branches and debris and stay indoors during the gusts.

MetService said it had already recorded gusts up to 100km/h in parts of Northland this morning.

“And ... the west coast of Northland and Auckland has the potential [to see] even stronger, damaging gusts.”

More than 2700 lightning strikes have also been detected since midnight, most offshore.

Five other strong wind watches have been issued for both islands. Northland will fall under a watch between 1pm and 9pm, Waikato north of Te Awamutu is under a watch from 3pm to 11pm, and the Bay of Plenty west of Kawarau is under watch from 4pm to midnight.

The Hawke’s Bay south of Hastings, along with the Tararua District, will fall under a watch from midday to 11pm tomorrow, while a watch comes into place for Dunedin, Clutha, Southland south of Gore and Stewart Island from 10am to 6pm tomorrow.

MetService said all watches it had issued on Sunday morning had a moderate chance of being upgraded to a warning.

Martino said springtime was typically the windiest part of the year.

“It’s pretty appropriate for the start of spring that we’re blasting into some strong westerly winds. And we do have another few days of pretty unsettled westerly fronts sweeping by,” she said.

Raphael Franks is an Auckland-based reporter who covers business, breaking news and local stories from Tāmaki Makaurau. He joined the Herald as a Te Rito cadet in 2022.