The Far North deputy mayor is worried about high tide, which is set to strike the eastern coast of the rain-soaked region at midnight.
Court told Checkpoint Kāeo was the worst hit area from the flooding, but the council was keeping a close eye on Awanui, Moerewa, Rangiahua and Kohukohu.
More problems could arise late tonight, she said.
"If this rain doesn't let up, given the current levels of flooding, we can expect to see it significantly worsen and in the dark in the middle of the night that's always a frightening prospect."
It was not yet known whether any homes would be evacuated, but Civil Defence had been activated and would take action if it was needed, Court said.
Travelling was slow and dangerous because there were lots of surface flooding, slips and trees down, she said.
People should not travel unless they had to and if they did travel they should drive slowly and be aware they could come across downed trees or powerlines, she said.
Many of the region's sewerage systems were under pressure at the moment because they had been inundated, she said.
Everyone should treat the stormwater as if it was contaminated, she said.
People should avoid showering, flushing their toilets and doing their laundry if possible.
The flood was one of the worst she had seen in some time and if the rain continued, the situation could be very serious by tomorrow, Court said.
Anyone who felt they were in immediate danger should dial 111 or if they were not in immediate danger they could dial 105 and they would make the call, Court said.
Trucks replace ambulances in Kāeo
Ambulances are being swapped by trucks to transfer patients from Kaitaia to Whangārei in the Far North town of Kāeo.
With several State Highways closed due to heavy flooding, the access to Kāeo's Health Centre has been blocked by the water and the measure is a precaution.
A Northland District Health Board spokesperson said residents who lived north of Kāeo should go to Kaitaia Hospital, while residents who lived south should go to Bay of Islands Hospital in Kawakawa.
Residents are also advised to stay informed by following Civil Defence Northland updates and check for road closures before travelling.
