Massive waves have caused extensive damage to the Coromandel's entire eastern coastline, including wiping out Brophy's Beach in Whitianga, as waves spewed across roads.
And more damage is likely, with Coromandel residents being urged to keep away from the coastline two hours either side of high tide until Saturday for their own safety.
Garry Towler, Thames-Coromandel District Council civil defence controller, said the forecasted high tides including king tides later in the week meant it could be "pretty dangerous" out there.
All roads were open in the Coromandel today, but Towler said the beaches were "an absolute mess".
Whitianga - particularly Brophy's Beach and Buffalo Beach - has been the hardest hit due to the angle of the harbour, he said.
"Brophy's Beach was the worst damaged. That beach was wiped out."
A deep low pressure to the northeast of the country continues to drive strong to gale force southeast winds onto the North Island. Overnight, observations in Coromandel, Bay of Plenty and Gisborne have seen combined waves (both swell and wind waves) between 4 to 7 metres ^KL pic.twitter.com/FsK0eiB1Dl
"They all suffered ... huge amount of sand movement. What that does is exposes a lot of rocks and exposes a lot of potential for erosion."
Every available TCDC staff member and contractor were carrying out rapid assessments and checking all the beaches to ensure the structures were safe, Towler said.
They were also working between the tides to push up sand in vulnerable places, clearing structures and removing debris to prepare for the next high tide at about 5pm.
Towler was also worried about the big king tides due to hit on Wednesday to Friday and was expecting similar levels of water breaches as those of yesterday afternoon.
"It will be much of the same. Luckily we don't have huge winds and luckily also we don't have a lot of rain, which would have come down from the catchments, which would have made things worse."
Once the king tides receded next week, the council would then move into recovery mode and start rebuilding the beaches.
"It will be quite an expensive fix, this one."
MetService shift meteorologist Ashlee Parkes said the worst of the high swells had already happened and it was now easing for most places such as Bay of Plenty and Coromandel.
MetService recorded waves overnight of up to 6.5 metres in Bowentown, near Waihi, and up to 8m in Pukehina, east of Tauranga.
Swell warnings have lifted for most of the country except the Gisborne District, which could see waves between 4.5m and 5.5m from now right through until Thursday.
Strong wind warnings are in place for the eastern Bay of Plenty and Gisborne north of Ruatōria. The northern Gisborne region and the ranges have a heavy rain warning in place with 70 to 90mm of rain to fall from 8pm last night to 11am today.
A heavy rain watch is in place for the south of Gisborne and strong wind watches are in place for the eastern Bay of Plenty ranges, eastern Taupō, eastern Taihape, inland Hawke's Bay and Taranaki.