Heavy rain is expected for parts of the North Island today. Photo: 123RF
Gisborne is keeping an eye on river levels as the drenched region has an orange heavy rain warning and a severe thunderstorm warning is also in place north of Auckland.
MetService warned residents to expect 60 to 100 millimetres of rain on top of what has already fallen before 6am on Tuesday.
The top of the East Coast has so far recorded the largest amounts of rain in the region, with Tai Rāwhiti Civil Defence saying Waikura Valley, has received 110mm in the 24 hours to 9am, and Ruatoria receiving 74mm in that same period.
There was also a heavy rain watch for Coromandel Peninsula and the eastern Bay of Plenty, while a thunderstorm watch was in place for Northland, Auckland and the central North Island.
Flooding between Ruatoria and Tokomaru Bay during Cyclone Gabrielle. Photo: RNZ / Kate Green
Tokomaru Bay Civil Defence spokesperson and local resident Lillian Te Hau-Ward said steady rain had fallen all night, while the top of the East Coast had had heavy rainfall.
The bay was "bracing" for that weather this afternoon.
"Our biggest concern still is Mangahauini dam," Te Hau-Ward told Midday Report.
Te Hau-Ward said they were keeping eyes on the awa (river) in case residents needed to be evacuated. They had told locals that is the river was flowing, everything was OK but if it stopped flowing, it was time to move.
"Our biggest concern still is Mangahauini dam" - Tokomaru Bay Civil Defence spokesperson Lillian Te Hau-Ward
On Sunday, the local Civil Defence pushed out warnings that anyone who was feeling anxious should evacuate to where they had previously felt comfortable.
She asked that those who chose to evacuate told Civil Defence "so we aren't running around looking for people".
MetService meteorologist Lewis Ferris told Midday Report another band or rain was strewn across already soaked regions.
It was "very, very unwelcome rain," he said.
"They'll need to keep an eye on the sky" MetService meteorologist Lewis Ferris
In the past 12 hours, 113mm had fallen on the northern area of the Gisborne region, and one area had 26mm in just one hour.
A severe thunderstorm watch had also been issued for much of the North Island until 9pm, Ferris said.
It did not mean all areas would see thunderstorms, but all were at risk.
"They'll need to keep an eye on the sky. If there is some really dark clouds they may get a downpour, that's the main risk."
Localised downpours could bring flash flooding, he said.
While heavy rain was expected to hit, Ferris said the North Island should see it clear by midday on Tuesday, and it may make its way down to the South Island where it may be more welcome.
Warning north of Auckland
MetService has upgraded its severe thunderstorm watch to a warning for people living Kaipara, Waitākere, Northland's Whangārei, Rodney, Albany in Auckland.
The thunderstorms are expected to be accompanied by very heavy rain and damaging hail.
A severe thunderstorm watch remains in force for Northland, Auckland, Waikato and the Bay of Plenty.
The National Emergency Management Agency said as the storms approached, people should take shelter, preferably indoors and away from windows.
Northland Civil Defence is advising travellers to seek up-to-date information on the region's roads.
Several routes remain blocked or compromised across the region.
Access to the region through State Highway 1 remains blocked in the Brynderwyns, with a detour available through Dargaville.
Access to Mangawhai is restricted to residents or freight deliveries.
Several other smaller roads in the surrounding area are restricted or closed due to slips and other damage.
Tropical cyclone in Pacific
Earlier, MetService head of communications Lisa Murray told Morning Report she was "confident" a tropical cyclone in the pacific would be named in the next 12-24 hours, but there was no certainty of where it was going to go.
Models were showing it going to the north-east of New Zealand and not hitting anything like Cyclone Gabrielle, she said.
However, large swells in the north and wind might be experienced, she said.
It's still happening and there's more to come unfortunately." MetService head of communications Lisa Murray
Murray said it was not unusual to see tropical cyclones this time of year, but climate change meant warmer air held more moisture.
This led to cyclones dumping more rain.
"When it gets here, winds are stronger, rains are heavier. It packs more of a punch," she said.