Wild weather has already swamped much of Waihi Beach but authorities are warning people the worst could still be to come.
More than 100mm of rain fell in the Western Bay of Plenty holiday spot overnight, with surrounding areas recording as much as 130mm north of Waihi Beach and 70mm in the south during the past 18 hours.
A screenshot of Metservice's rain radar at midday shows more rain on the way for the Western Bay of Plenty. Image / Metservice
About 150 campers at Waihi Beach Top 10 Holiday Resort were evacuated early this morning after the river breached its banks in several places. Read more here. Many campers have since packed up and headed home as more rain is predicted to come this afternoon, leading into Christmas Day tomorrow.
The National Institute of Water and Atmospheric Research dubbed the wet-weather system responsible a tropical "firehose" of moisture.
MetService has issued a severe weather warning for Northland, Coromandel Peninsula and Bay of Plenty, including Rotorua, Gisborne north of Tolaga Bay.
Waihi Beach resident Sheila Washington with dog Poppy says floodwaters were at one point over her knees. Photo . George Novak
Meteorologist James Millward said the wet weather drenching much of the upper North Island was set to continue, particularly in the Waihi Beach and Western Bay of Plenty area.
"We can expect another 90-100mm to accumulate over that period. It's not done yet," he said.
"There's more rain coming. We'll have another wet 12-18 hours. There will be a bit of a brief reprieve. You might even see a little bit of sun but we are expecting more heavy and thundery falls in the morning. So it will be a pretty wet Christmas Day.
"Beyond that, Boxing Day actually looks reasonably pleasant around the country."
Waikato Regional Council has today warned of potential road closures in and around the Coromandel Peninsula as a result of the heavy rain and king tides expected between 9pm and 9.30pm.
Floodwaters at Waihi Beach have dampened holiday plans for some campers. Photo / George Novak
Regional hazards team leader Rick Liefting said the council has been keeping a close eye on things, concerned at further flooding in some places.
"This could result in road closures in places like the Criterion Bridge on SH26 at Paeroa, the Karangahake Gorge, the entrance to Thames at Rhodes Park and SH25 at Hikuai. If this happens, then it's likely to occur a few hours either side of high tide, so potentially between 7.30pm and 11.30pm today."
Liefting said the council was also wary of slips and encouraged people to avoid road travel as early as possible this evening or to delay their travel until tomorrow.
Waihi Beach Top 10 Holiday Resort owner Ian Smith said the river breached its banks in several places and was "rising rapidly" when he went to survey the area about 3am.
Smith, a former fire chief of Waihi Beach fire brigade, said the evacuations "was about managing risk, to act sooner rather than later".
Much of Waihi Beach Top 10 Holiday Resort was under water this morning, and more rain is expected to come this afternoon. Photo / George Novak
Campers were told to pack up their blankets and head to the local RSA, which hosted the evacuees for the night.
Flood waters in some areas of Waihi Beach were knee-deep.
"A lot of people were hoping to spend Christmas Day here and had their plans thwarted. That's a shame," Smith said.
