There was a "very real possibility" Auckland Harbour Bridge could close because of strong winds, as a wintry blast hits the country, bringing snow to the South Island.
Snow is covering parts of Southland and Otago, and in the North Island the Desert Road was closed overnight but has now reopened.
Speed limits and lane reductions had been in place on Auckland Harbour Bridge due to severe wind gusts but it was currently fully open.
Auckland Transport manager Richard Harrison told Checkpoint wind gusts were expected to get worse between now and 9pm, and they were waiting to see what would happen with the bridge.
Harrison said there was a "very real possibility" it could close tonight and there were "some very real safety concerns" - referring to a truck accident which damaged the bridge's infrastructure in 2018.
While AT sometimes received advance warning from forecasters, decisions on closures were often made on the spot, Harrison said.
If there was a closure, he said buses would be stood down in place for 30 minutes, as wind gusts could be transitory.
There were also plans for detours if there were sustained wind gusts.
Harrison said customers should check the Auckland Transport app for any potential changes to their journeys.
Earlier, Waka Kotahi issued a red alert through to 9pm, with wind gusts of 90-100 km/h forecast, and possible gusts of 100-110 km/h. If those alert levels were triggered all lanes on the bridge would be closed, Waka Kotahi said.
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.
In the South Island, Waka Kotahi is advising motorists to take care on icy roads in Southland and Otago after the cold blast over the weekend closed some state highways.
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