Holidaymakers in the Coromandel are being told to hunker down and not to leave until the worst of the bad weather set to batter the region eases.
Thames Coromandel District Council is bracing for flooding, slips, gale-force winds, power outages and further road closures in the next 24 hours.
Its emergency operations centre has been activated as civil defence and emergency services prepare for the storm to cause havoc.
MetService has issued a heavy rain warning for Coromandel Peninsula from 1pm today until 6pm tomorrow.
Between 120 and 160mm of rain is expected to accumulate during that period.
The Coromandel is expected to be the hardest-hit region, despite heavy rain and strong winds expected to hit most of the upper North Island today.
A heavy rain watch is in place for Auckland, Gisborne and for parts of Bay of Plenty, and gale easterlies are likely to hit Northland, Auckland, Coromandel Peninsula and northern Waikato.
Thames District Council civil defence controller Garry Towler said the worst of the storm was expected to hit the region overnight and warned people to get prepared.
"Secure outdoor furniture, check gutters and drains in your neighbourhood, check that your neighbours are okay, set up gas appliances and torches in case power goes out, charge phones and then just hunker down. It will be over by mid-afternoon on Monday."
He also urged all travellers, especially in motor homes, to stay put and not try to get off the Coromandel until the bad weather passed.
Gale-force winds would make driving tricky in wind gusts in excess of 100km/h and could blow over motor homes, as well as caravans and trucks, he warned.
"We have been safe with Covid-19, let's be safe with this one as well, it will pack a punch," Towler said.
A large slip has forced the closure of Rangihau Rd in Coroglen.
The Thames-Coromandel District Council expected the road to be open to just one lane by 3pm Monday.
"Please avoid travel," it urged.
NZTA Waikato system manager Cara Lauder encouraged motorists to take care and stay alert.
"Heavy rain may cause streams and rivers to rise rapidly. Surface flooding and slips are also possible and driving conditions may be hazardous.
"Drive to the conditions and watch out for surface flooding, slips and fallen trees or branches. Check your intended route for hazards or disruptions before setting out, using the Transport Agency's Journey Planner website, and remain alert for unreported hazards.
Meanwhile, SH25 between Hikuai and Whitianga has re-opened after heavy rain overnight caused flooding and slips, closing the road for several hours on Sunday morning.
An underslip at the top of Pumpkin Hill on SH25 north of Tairua has closed the road shoulder.
Temporary speed limits and traffic management are also in place in a number of locations and contractors are working to clear waste and debris after last night's heavy rain.