Health officials warn that nasty stomach bugs could become the order of the day - with shellfish and wet fish off the menu - as the storm that brought widespread damage and flooding across Northland continues into the weekend.

Strong winds and heavy rain battered Northland again yesterday from a storm that first hit the region on Tuesday with winds up to 160km/h.

The MetService warns more is likely today before things tail of, hopefully from tomorrow, though winds aren't expected to top 100km/h in exposed areas.

About 30 boats across the region were sunk, slipped their moorings or washed onto shore as wind and waves battered the coastline with more roofs blown off, trees down and flooding.


More than 7000 properties across the region will have spent last night without power as linesworkers from Top Energy and Northpower worked furiously yesterday to restore electricity to the more than 17,000 without power the previous night.

Top Energy says it is the worst damage to its network in at least a decade, with the wind so powerful sturdy concrete poles were snapped in half, forcing the company to rebuild parts of its power network from scratch. At the storm's peak about 11,000 households - almost a third of those in the Far North - were without power.

Top Energy hoped to have the number without power overnight down to 6400, with some of those spending a third night without electricity.

Northpower expected to have leaving less than 1000 without power overnight in Whangarei and Dargaville. But Northpower's efforts have been hampered by thieves who put their lives at risk to steal 300m of 11,000 volt power line that had been downed on Opouteke Rd, near Twin Bridges.

"There is every possibility that the line could have been live, so the company is again stressing the common sense approach around electricity network safety," Northpower Public Affairs Manager Steve Macmillan said.

As flood waters rose across the region - including the Northern Wairoa River in danger of topping its banks at times - a truckie had to be rescued after this vehicle got inundated on Swamp Rd, Hikurangi.

The driver got out of the cab and onto a spot of dry land among the flood waters and had to be rescued by a local farmer in a large tractor.

Northland District Health Board's Medical Officer of Health Clair Mills has issued a general region-wide advisory warning people to stay out of waterways, flood waters and harbours to avoid contact with contaminated water.

There are a number of nasty problems that can occur from going into contaminated water, including gastrointestinal illnesses; skin infections and respiratory infections.

Whangarei District Council Infrastructure and Services Group Manager Simon Weston said there will be a range of contaminants in all flood water, streams, rivers and the harbour as a result of the prolonged rainfall.

"Our waste water treatment plant is discharging treated effluent, not raw; the Hatea pumping station has operated according to plans, and where there have been power cuts we have had sucker trucks and generators at pumping stations," Mr Dell said.

"The advice is to keep out of the water until it is clear (generally five days after the storm ends) and not to consume shellfish or wetfish."