Huge swells and 10m-plus waves are set to thrash the coastline in coming days.
Niwa reports on Twitter big wind in addition to king tides will create the monster waves. The waves will arrive later this week and early weekend.
Meanwhile, the king tides are likely to occur between August 1 and 6 and there will be an increased risk for coastal erosion and flooding.
Large waves were tipped to reach heights of up to 4m along our coastline in March, with offshore waves measuring 10m.
Hokitika and Greymouth were told to expect waves up to 3.5m with Jackson Bay likely to reach 4.5 to 5m. Campbell Island and the Auckland Islands were tipped to expect waves 7m high.
In April, waves across the Tasman Sea reached heights of 14m but were only tipped to scale 8m high on our shores.