Rain-sodden Northland can't take much more as some areas have already received up to three times more than normal for February, says Civil Defence Northland.
MetService is forecasting more rain tomorrow and intermittent showers on Thursday for the already soaked region.
The forecast for wet weather comes after Fire and Emergency New Zealand set up a Whangarei co-ordination centre to monitor flooding hotspots at the Turntable Hill in Moerewa and the Three Bridges in Kawakawa.
Northland Civil Defence Emergency Management spokesman Murray Soljak said Northland normally recorded between 60mm and 100mm of rain for February.
But areas in the Far North and the eastern hills from Cape Brett to Whangarei Heads had already had up to 250mm to 300mm - or more than two to three times the normal for the month - just halfway through February.
Catchments in these areas were at full capacity and would remain that way in the coming days, he said.
"Any significant rain will run straight off into the land and lift the rivers a lot quicker than normally observed in hot summer conditions," Mr Soljak said
Muriwhenua area fire commander Wipari Henwood said volunteer firefighters were on standby tonight in case flood waters rose and people needed to be evacuated.
The centre was set up at 12pm today at the Whangarei Fire Station.
At 4pm today water was lapping under Turntable Hill bridge on SH1 and on both sides of the road at the Three Bridges at Kawakawa.
Mr Wipari hoped water levels at the two locations did not rise during or after the high tide at 7.25pm tonight.
"Unlike other areas in Northland, water catchments in Moerewa and Kawakawa have a delayed effect which means it takes time for water levels to rise," Mr Henwood said.
"If water levels rise, we'll pre-deploy crews from Kawakawa to Moerewa before the area becomes isolated and backfill crews from other areas into Kawakawa.
Mr Wipari said firefighters were also keeping a close eye on Kaeo and if water levels rose, crews from Kerikeri and Mangonui would be brought in to help.
MetService meteorologist Cam Coutts said rain tomorrow would not be as heavy as Monday evening.
Rain should clear tomorrow night with odd showers on Thursday.
Meanwhile, the wet weather closed 16 schools and one early childhood centre in Northland.
The early childhood centre which closed was Kaeo Playcentre.
A number of roads were also affected by the rain.
State Highway 1 at Rangiahua, 14km west of Okaihau, was closed at 1.45pm today after a flooded stretch of road became impassable.
Traffic was detoured through SH10.
New Zealand Transport Agency contractors were working on a slip that caused the closure of SH11 at Lemons Hill, between Kawakawa and Paihia, at 7.50am today.
A logging truck rolled off Mangakahia Rd near Titoki about 4.15am today but the road was not blocked.
No one was injured.
The Twin Bridges were flooded for north and southbound traffic about 2.30pm today.
In the 48 hours to 4pm today Pouto Point and Whakapara received 90.5mm of rain, Kaeo 91.5mm, Waitangi 86mm, Awaroa 79mm, Kerikeri 76mm and central Whangarei 43.8mm.