A heavy rain warning is in place for Rotorua and the Bay of Plenty tomorrow.
MetService said a front remained slow-moving over the northwest of the South Island today then will move onto the North Island tomorrow before moving east of New Zealand on Friday.
The heaviest and most prolonged rain is forecast for the Bay of Plenty, Nelson, Mt Taranaki, and the ranges of Gisborne.
About 100 to 140mm of rain is forecast for the eastern ranges of Bay of Plenty, and the Gisborne ranges from 6pm tomorrow until midday Friday with 70 to 100mm elsewhere.
Downpours are also expected in Taupo from tomorrow afternoon.
Meanwhile Cyclone Donna will be sitting roughly 300km offshore and downgraded to a Category 2 cyclone by lunchtime today, but is still a Category 3 at the moment, the MetService said.
Donna's remnants will hit off the coast of Kaitaia at midnight on Thursday and will take another day to travel down to the Gisborne area.