Stop-go workers are busy directing traffic along the coastal road, where waves have been swamping the road.
Debris was strewn across the road around the bays and cars were forced to pull into opposite lanes in an effort to avoid the sea water crashing on to the land.
High tide was just after 9am, meaning the ferocious waves are on their way out. While high tide is due again about 10pm, the winds should have died down by then, taking much of the flood risk with them, Metservice said.
A combination of the high tide, a king tide yesterday, the strong winds, and the storm surge created the flood risk, meteorologist Tom Adams said.
Parts of the South Island such as Banks Peninsula also faced the same risks, but the heavy winds are expected to ease by 3pm.
Marlborough also has a strong wind warning out.
"Waves out in the Cook Strait at the moment have levelled off at around four and a half metres or so. The max waves have been up around 7m. They could grow a little bit yet but the risk is less tonight."
While the flood risk is waning, residents still need to prepare for hazards caused by high winds, gusting up to 120km/h in exposed places.
The highest wind gust for the country in the past few days was in Northland on Thursday when the storm began, at 161km/h.