Hawke's Bay officials were preparing for possible flooding, with the regional council calling back staff from leave after MetService issued heavy rain warnings.
"Our team has been called back from leave and includes staff on the ground in Wairoa, closely monitoring river levels and looking to potentially open minor river mouths in the area should the need arise," Hawke's Bay Regional Council said in a statement on Wednesday.
"Currently the Wairoa River mouth is performing well and we will be closely monitoring the mouth during the period of high swell.
"From Esk to Māhia, we expect rivers to rise and remain within their channels, although we urge the community to be mindful that levels may rise quickly in heavy rain."
MetService issued an orange heavy rain warning for Gisborne/Tai Rāwhiti and Hawke's Bay north of Napier, as well as a strong wind watch for the coastal areas of Hawke's Bay, Gisborne/Tai Rāwhiti, Kapiti Coast, Wellington and coastal Marlborough including the Sounds.
In Gisborne/Tai Rāwhiti, heavy east to northeast rain was expected to set in from around 6am, becoming south to southeast late on Boxing Day.
Between 100 to 120 mm of rain was expected, with a peak of 15 to 25 mm/h on Thursday afternoon.
Thunderstorms were also possible.
In Hawke's Bay north of Napier, between 110 to 130 mm of rain was expected, especially in the ranges, with a peak to 10 to 20 mm/h, from around 9am on Thursday morning to 1pm on Friday afternoon. However, heavy rain may continue into the Wairoa District into Saturday.
MetService warned surface flooding, slips and difficult driving conditions were possible.
However, it said there was only a minimal chance of upgrading to a red warning.
"We're closely monitoring the situation and will share updates if anything changes," the Hawke's Bay Regional Council said.
In the coastal areas of Hawke's Bay and Gisborne/Tai Rāwhiti, southwest winds may approach severe gale in exposed places from around 1pm on Friday afternoon, with a moderate chance of the strong wind watch being upgraded to a warning.
There was a similar warning in place for Kapiti Coast, Wellington and coastal Marlborough including the Sounds between 1am and 3pm on Friday.
