Residents along Wellington's south coast are being warned of potential flooding and inundation tomorrow.
In a tweet, NIWA Weather said parts of the lower North Island including the south coast of Wellington "may experience coastal flooding/inundation" on Wednesday.
It said this is due to a combination of a significant wave height near 6 metres and a king tide.
MetService has issued a heavy swell warning, which comes into effect from 7pm Tuesday and lasts until 3pm Wednesday for Wellington - Cape Terawhiti to Turakirae Head.
Combined with the king tide and strong southerly winds, inundation was especially possible for the two hours each side of Wednesday morning's high tide.
"SH2 could see minor wave splash across the tracks and southbound land of SH2," MetService's website said.
"Despite the king tide, a limiting factor could be the air pressure which does not get very low."
The king tide is expected at 5:50am and 6:20pm on Wednesday.
A Wellington City Council spokesperson told Newshub officials are keeping a "close watch" on the situation and will "start closing roads" if the swells pose a threat.
"If things get really extreme evacuations are possible," the spokesperson said.
"If the wind starts blowing really hard then people are advised to stay away from the southeast."
Wairarapa - Turakirae Head to Mataikona is under a heavy swell warning too from 4am Wednesday to 9pm Wednesday.
MetService is urging anyone who is planning to be in or near the water to "make sure and check out the marine forecasts".
