On the Cooks Beach Community Facebook group, Penny Yates posted images of a boat being grounded at the beach.

"Sad to see this on front beach presumably from Flax Mill Bay," she said.

"Looks like the anchor rope is snapped."

Fire crews across the Bay of Plenty were kept busy overnight as wild weather battered the region.

As trees came down and debris was flung across roads, crews were called to about five separate weather-related incidents within 12 hours.

The Coromandel Peninsula was hit the hardest, with roads closed and flooding.

The Kopu area had the largest amount of rainfall in the whole country, with a whopping 204mm within 24 hours.

UPDATED high-resolution forecast of expected rain totals and wind gusts.

Main impacts:
1⃣ Increased risk for slips & localised flooding.

2⃣ Elevated risk for tree damage & power cuts due to combination of wind & rain.

3⃣ Risk is elevated further due to unusual wind direction. pic.twitter.com/lDqLvv0YqY

— NIWA Weather (@NiwaWeather) May 31, 2020

Police say caution is required on SH1 between Warkworth and Wellsford.

"Heavy rain in the area has caused damage to the road surface, so motorists are asked to slow down and drive to the conditions," they said in a statement.

Anyone holidaying in the Coromandel Peninsula can expect a further 100mm to 130mm of rain to accumulate on what has already fallen - with peak rates of 20mm to 25mm an hour expected early this morning and afternoon.

Up to 130mm of rain is forecast over Gisborne, north of Tolaga Bay, and the eastern ranges of the Bay of Plenty. People there are also being urged to keep an eye on updates throughout the day.

Northland - especially in the eastern ranges - was expected to get a further 70mm to 90mm by early this morning.

The Thames-Coromandel District Council is asking people to delay travel as a large tree has fallen on the Manaia Road highway.

"Contractors are working on this and the road is now open to one lane with stop/go traffic management in place, along with various other sites across the State Highway network," the council said in its 10am update.

Civil Defence Controller Garry Towler said: "There is a lot of water coming down and our streams are rising rapidly."

He said high tide was expected at about 3pm this afternoon and people need to be prepared for considerable delays and be prepared to stay "until the last band of rain clears later this evening".

Tairua and Pauanui Refuse Transfer Stations are closed.

In Auckland, especially north of the city, a heavy rain watch remains in place until later this morning. The same rain watches are in place for Great Barrier Island and the Hunua Range, south of the city.