MetService has stepped up heavy rain warnings for Gisborne and the ranges of Hawke's Bay.
A vigorous low is forecast to pass about 100km northeast of East Cape about noon on Tuesday, bringing rain to much of the North Island.
The rain and gales on the East Coast should ease slowly during Wednesday, but there will probably be between 120 millimetres and 250mm falling until then.
MetService says this is more rain over a longer period than anticipated earlier.
Slips are likely on many roads in hilly country, while streams and rivers are likely to rise.
Winds on Tuesday are forecast to rise to gale force gusts of 100km/h an hour in exposed places east of about Opotiki to Tolaga Bay.
Civil Defence in Gisborne is expecting 180mm of rain in the region by midnight on Tuesday.
Civil Defence manager Richard Steele says staff will monitor river levels and flood wardens will contact residents in low-lying areas if the situation deteriorates.
Mr Steele says rivers which have been rising since Sunday should cope with the heavy rain, but there could be surface flooding in some areas. Flooding and slips on Monday forced the temporary closure of several roads in the city and outlying areas.