Heavy rain is on the way to Bay of Plenty, with 90mm to 110mm expected within 15 hours as far west as Ōpōtiki.
MetService said a heavy rain warning was in place for the areas east of Rotorua, with heavy rain gradually easing from the west.
The areas east from Ōpōtiki were lined up for the heaviest rain particularly around the ranges, with peak falls of up to 20mm an hour for a total of 90mm to 110mm until about midnight.
About 40mm to 60mm was expected around the rest of the region, possibly with thunderstorms in areas.
The Kaikōura ranges were also expected to be hit by further heavy rain on top of current falls, with 30mm to 40mm likely between 9am and 2pm today.
Flooding from those earlier falls also closed State Highway 1 further north, between Blenheim and Clarence at Tirohanga Bridge.
Drivers were also warned that streams and rivers in Kaikōura were likely to rise rapidly, with surface flooding and slips possible.
It came as a counterpoint to a warm spell in the South Island's southwest, with Haast and Milford Sound breaking records for their warmest October temperature yesterday.
In Milford Sound, the temperature hit 25.2°C yesterday afternoon, knocking down previous October records going back to 1933 and its second-warmest recorded day of spring, NIWA Weather said.
Haast reached 23.2°C, its warmest October day since records began in 1949.