MetService has lifted heavy rain warnings for most parts of the North Island but says heavy rain will persist for time in the Bay of Plenty.
It says a tropical low is beginning to weaken and is expected to move eastwards across the top of the North Island on Sunday.
But MetService says a warm and humid northeast flow will linger over the Bay of Plenty bringing further bursts of heavy rain.
It also warns that further flooding and slips are possible and driving conditions may be hazardous in the region.
Earlier on Saturday, Waikato police described driving conditions around the Coromandel Peninsula as "atrocious" and warned motorists against all unnecessary travel in the area.
They said the rain had reduced visibility considerably while there was some surface flooding and roads were generally wet and greasy from the rain.
A car was swept away as it attempted to cross a river ford near Whangamata
The two occupants managed to escape but Wentworth Valley Road, southwest of Whangamata was closed and will not re-open until the rain finally ceases.
State Highway 29, between Waikato and Tauranga was also closed by a slip about 3km east of Old Kaimai Road.
Meanwhile, heavy rain in Wellington caused an overflow of sewage from the Moa Point treatment plant and prompted a warning for swimmers and surfers to avoid using the beach at Lyall Bay until at least Monday.