"It's going to take time - 1-2 weeks and we're still in a live situation. We're expecting more heavy rain this afternoon,'' he told Newstalk ZB today (Friday).
While the deluge had eased for most areas today, more heavy showers were approaching Nelson, reported WeatherWatch.co.nz.
"We're not out of the woods just yet'', said head weather analyst Philip Duncan.
"These showers are heavy and big enough in size to again bring the threat of more flooding and landslides because the ground simply cannot take anymore water.''
There have been more than 200 slips in the region and last night a dozen homes above Nelson's Rocks Rd were evacuated after a house started to move on unstable land.
Others in the Tasman region remained stranded in blocked off areas or unable to return to their homes and the Golden Bay settlement of Collingwood was cut off due to a wash out at Bird Hill.
Mr Miccio described the deluge was "the worst in 40 years''.
The rain swept north yesterday to soak Auckland, Bay of Plenty and Northland, keeping emergency services busy as flooding washed over roads and bridges.
Thunder, showers and strong winds are expected to keep hitting the North Island today.
Emergency services were kept busy as the downpours hit between Kaeo and Kerikeri in the Far North, where there was widespread surface flooding, reducing roads to one lane in places.
Northland Regional Council hydrologist Dale Hansen said some areas had had between 75mm and 125mm of rain overnight yesterday, on top of 50-70mm of rain in previous days.
A month's worth of rain also hit the Bay of Plenty overnight, with Metservice recording 54.8mm for the period and more showers ahead for Tauranga, said Metservice forecaster Chris Noble .
"As we go into Saturday you have this big low that has been causing all this trouble, that crosses over the North Island around the middle of the day,'' he said.
A MetService forecast to midnight tonight included rain from Auckland to Kapiti, including the Bay of Plenty, clearing from the west.
