Police warned people to avoid travelling in parts of Northland on Saturday night as thunderstorms again threatened the region with flooding.
The Fire Service said three homes in Maungaturoto, south of Whangarei, were flooded on Saturday.
At least 50 millimetres of intense rain fell on Saturday, closing State Highway 1 at Brynderwyn Hill between Auckland and Whangarei.
Fire crews also helped the drivers of stranded vehicles, one at Maungatoroto and another that was cut off by flooding on state highway one north of Waipu. Another vehicle was stuck in floodwater at Tutukaka.
Floodwaters had been receding following fine weather during the past six days. But Northland Civil Defence spokesperson Graeme MacDonald said last week's flooding meant groundwater levels had risen sharply, causing localised flooding.
"Some areas in Northland, particularly between the Bay of Islands and south of Whangarei, have had up to about 50mm of rain.
"But just in the last hour or two we've seen some localised high intensity falls up to 30mm per hour."
Mr MacDonald said the worst affected areas were around Whangarei, the Bynderwyns and inland towards Dargaville.
MetService said more heavy rain was expected overnight.
Extra police have been rostered on in Northland to deal with weather-related incidents.