Bay of Plenty Civil Defence and Tairawhiti Civil Defence have issued heavy rain warnings for the region as the remnants of Cyclone Donna bring torrential rain to much of the North Island.
The ex-cyclone is expected to bring more than a month's worth of rain in two days for some areas.
Rainfall will be heaviest in the Bay of Plenty and Gisborne, with falls of up to 250mm in the ranges and 100-140mm elsewhere in the region.
The rain is expected to fall between 9pm tonight and 6am Friday.
A MetService heavy rain warning is also in place for Waitomo and Taupo across to Whanganui, as well as the Coromandel Peninsula. Those areas can expect another 70-90mm of rain overnight, with peak rainfall to reach 25-35mm in an hour.
"What if there was no power, no water or no communication? If there is heavy rain coming, have you cleared your gutters or thought about your pets? A little bit of planning goes a long way," he said.
Local residents are advised to stay updated by listening to local radio and watching the BOP Civil Defence Facebook page and website, which offers a text alert service.
The Met Service has also issued a severe thunderstorm watch for Kaitaia down to the Bay of Plenty, which lasts from this afternoon through till 3am on Friday.
Severe weather warnings are in place across the middle of the North Island.
"Localised downpours are possible across the entire region," regional hazards team leader Rick Liefting said.
Catchments were still saturated in many places after recent severe weather which could add to flooding-related risks and accumulation of surface water, he said.
"However, council staff are confident that flood management schemes will handle the forecast rainfall."
Liefting said it should start to fine up tomorrow afternoon. He urged people to stay up to date with weather forecasts and warnings.
Edgecumbe's stopbanks are prepared, according to the Whakatane District Council, after they were overwhelmed by rain from Cyclone Debbie in April.
Waikato Regional Council says it is watching rain and river levels closely as heavy downpours are expected to last through till tomorrow.
WeatherWatch said after ex-cyclone Donna passes by on Friday and Saturday a large high would come from the Tasman, bringing settled weather for three to four days.
The coming weeks may see a similar pattern of lows followed by highs, WeatherWatch said.
"When you zoom out and look due west around the globe you notice a pattern - high, low, high, low, high tracking eastwards towards the New Zealand area."