Fire Service officials rescued several people trapped in cars and homes, after parts of Northland were hit by two months' of rainfall in two days.
The bad weather swept further down the North Island yesterday, and strong winds caused flight disruptions at Auckland Airport.
Five incoming domestic flights were diverted or sent back to their origin.
And the Volvo Ocean Race yacht Abu Dhabi was last night sheltering in the Hauraki Gulf, waiting for 60-knot conditions to ease before resuming the round-the-world race after being forced to turn back with a damaged bulwark on Sunday evening.
More rain is expected to batter the drenched and battered Northland region until noon today, and another deluge is forecast for late tomorrow.
The 61-year-old woman was plucked from a river near Otaika, south of Whangarei, yesterday morning.
She had tried to cross a bridge in her car before the river overflowed but became stuck.
When she scrambled from her vehicle, she was washed downstream by a fast-moving current.
Her neighbour, Dick Pickering, said he used his kayak to reach her, and with the help of a fire crew in an inflatable boat she was pulled to safety.
"She was lucky enough to grab hold of [a] totara tree in the creek. It was going pretty strong. She'd been there for quite a while.
"She's a very, very lucky girl."
The woman was in a state of shock for the rest of the day, he said.
Further north, the fire brigade rescued a couple and their 3-year-old child from a Ngunguru home after 1.5m floodwaters threatened to engulf their property.
Firefighter Chris Gibbs said water was creeping up the walls of their home, and the fire brigade had to ferry them in an inflatable boat across 400m of floodwater.
More than 200mm of rain had fallen in parts of Whangarei between midnight Saturday and yesterday morning.
The heavy rain and strong winds caused numerous road closures and felled trees, and schools in the region were also closed for the day.
The low-lying Far North township of Kaeo faced even greater deluges, with 283.5mm of rainfall in the hills above it; twice the normal rainfall for the area for the whole of March.
Roads in and out of the township were closed, and floodwater in the main street rose to 1m deep.
