Just before 9am on Sunday, Fire and Emergency New Zealand (Fenz) said it was dealing with multiple incidents throughout Northland. It was making plans to access properties, and was only able to respond to immediate life-threatening situations.
People affected by the flooding should to go to higher ground and be cautious to stay safe, but call 111 immediately if they were in life-threatening danger, Fenz said.
There had been a report of a landslide in the township of Ōakura, but no people or cars had been trapped underneath.
A bridge had also been washed out, and multiple houses flooded near Whangaruru Harbour, Fenz said.
The Ngaiotonga Bridge had been washed out at the turn-off to Bland Bay and Whangaruru North Rd, cutting off residents to the south at Punaruku, the Whangaruru North Residents and Ratepayers Association said in a Facebook post.
They asked people with contacts in the area to call residents and whānau to warn them, and check they are safe.
Whangārei District Council said drivers should not travel in or out of Ngunguru, Helena Bay, Ōakura, Punaruku, or Whangaruru.
Police asked people to delay travel in the area if possible due to flooding and slips: "Police have received multiple calls this morning reports of intense flooding and slips in the Whangaruru, Oakua, and Helena Bay areas, especially on Russell Road.
"Thankfully, at this stage there are no reported injuries," they said.
"Motorists are advised to take extra and avoid travel due to flooding and slips between Whangaruru and Helena Bay."
MetService forecasters issued a heavy rain warning for Northland through to midday Sunday, with a warning the rain was expected to continue to accumulate after flooding overnight.
Nearly 150 millimetres of rain was recorded at Ngunguru between midnight and 5:30am today.
Areas south and east of Kawakawa had been especially hard hit.
Whangārei District Council said heavy rain and surface flooding had closed roads, isolating some communities.
"Drive with great care expecting slippery roads and possible hazards like fallen trees or flooding," they said on Facebook.
"Expect river and stream levels to be much higher than usual, and to be flowing with a lot more force. Levels may also continue to rise rapidly."
Whangārei mayor Ken Couper said Old Russell Rd was impassable after a bridge washed out. A slip in Helena Bay had washed on to the road to Rawhiti, and flooding had also hit Whakapara and Punaruku.
Fenz was coordinating the response, and Civil Defence was ready to respond if required, Couper said.
Hundreds in Northland had also woken up to find they had no power on Sunday morning.
Northpower said there were power outages for Helena Bay, Ōakura, Punaruku, and the Whangaruru Peninsula, and about 750 households appeared to be affected.
