The problem was the front bringing the rain wasn’t moving, he said.
That meant it kept raining in the Far North, including some “intense bursts”.
There were some thunderstorms overnight and that watch runs until 10am Thursday. The heavy rain warning runs until midday Thursday and Law said the rain should start to slowly move away later on Thursday.
Northland Regional Council’s Kaeo webcam showed flood waters accumulating before 6am.
Nearly 400 households were without power from Rawene to Waiotemarama, including Whirinaki early on Thursday morning.
Some 300 households around Rawene have had their power restored and just over 50 properties between Whirinaki and Waiotemarama remain without power.
The cause of the power outage was being investigated.
Waka Kotahi/NZ Transport Agency said there was flooding on State Highway 10 between Kaeo and Mangonui.
“Due to flooding between Ness Rd and Otangaroa Rd, one lane is closed with temporary traffic management in place.”
Motorists were warned to expect delays and take extra care.