Coromandel residents, including farmers, are waking up to what are expected to be extensive landslips after a one-in-15-years storm at the weekend.
But despite a weekend deluge Auckland's water storage levels have increased by only 1 per cent, with storage at 44.5 per cent of capacity.
Heavy rain in the region closed State Highway 25 on the eastern Coromandel for much of the weekend after flooding covered the road between Hikuai and Tairua.
A gobsmacking 520mm of water was recorded in a rain gauge at the Pinnacles on top of the Coromandel Ranges as of 6pm yesterday.
A marine salvage operator is expected in Whangamatā today to pump water out of a fishing boat which listed to one side under the weight of the rainwater, sparking fears of a fuel spill.
The rain eased last night, but Thames-Coromandel District Council civil defence controller Garry Towler said there were likely to have been many landslips.
"Farmers will be mopping up for a long time and there are some slips and washouts on farms, especially on the eastern seaboard."
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Rick Liefting, Waikato Regional Council's team leader for regional resilience, said the regional council, district council and NZTA would investigate ways that the region could be made more resilient to similar future events.
"The rainfall total at one of our rain gauges at the Pinnacles on top of the Coromandel Ranges, as at 6pm tonight [Monday], was 520mm. That is approximately a 15-year return interval event.
"But there were a number of events which compounded over March and April 2017 which reached up to a 100-year event."
The same low-lying area between Hikuai and Tairua also flooded then.
"That's an area where we are wanting to work with our partners to see how we can be more resilient," Liefting said.
"There may be some infrastructural changes that might be required. That would be further down the track. The first thing is to understand the rainfall systems that cause these sorts of events."
Elsewhere, in Auckland, a crash on the Southern Motorway in the far right lane heading north near Papakura is causing delays.
The incident took place around 7am, however, it has since been cleared but delays are still likely to occur in the area, NZ Transport Agency said.
In the Queenstown Lakes area, grit was applied to the Crown Range and some spots on Fernhill in Queenstown to assist traction on the roads.
And State Highway 25 at Hikuai, which was set to be closed overnight due to flooding, was reopened at 11.30pm.
NZTA Waikato/BoP asked motorists travelling on SH25 to take care on their journey.
In Christchurch, motorists heading into the city should take extra care on Tram Rd at the State Highway 1 off-ramp following a crash.
Meanwhile, the Gisborne District Council is warning Tauwhareparae Rd is closed at the 20km mark due to a slip.
Contractors were working to clear debris from the road and it was expected to be reopened by 10am.
Tiniroto Rd remained closed at the 35km mark - contractors were also on the scene there and it too was expected to be reopened by 10am.
Coromandel's west coast narrowly missed being flooded too. The regional council said at 3pm that it was "closely monitoring the Kauaeranga River and spillway on SH25, the approach to Thames opposite the sports ground".
"Should the spillway operate that will restrict traffic entering and leaving Thames. If the spillway operates it will be around high tide at 1500 hours [3pm]," it said.
As it turned out, the spillway did not need to open and traffic was unaffected.
Liefting said conditions were too rough to deploy booms to prevent an oil spill from the fishing boat at Whangamatā over the weekend, but salvors were expected today.
"They will pump the freshwater out and ensure that no more diesel will escape as their priority.
"Because it is a light hydrocarbon, the impact on the environment is likely to be very low because it will dissipate quickly."
A yacht was also blown off its moorings in Mercury Bay and ended up on rocks in Flaxmill Bay.
In Auckland, water storage dams increased by 1 per cent over and as of Tuesday morning were 44.5 per cent full - they were at 43.59 per cent yesterday.
The normal level at this time of year is 76 per cent.
The rain was heavier in the Hunua Ranges where 48mm was collected, compared to just 4.5mm in the Waitakere Ranges, spokeswoman Maxine Clayton said.
MetService forecast today for Auckland, Waikato, Coromandel, Bay of Plenty and Taupō is for mainly fine weather about Bay of Plenty and Taupō, but cloudy periods and the odd shower elsewhere.