Property owners in Wanganui and Palmerston North are mopping up today after an afternoon deluge yesterday that sent water cascading into some buildings.
The MetService said 64mm of rain fell in Wanganui yesterday and 51mm in Palmerston North - the bulk of it over a very short time.
Palmerston North police yesterday reported major surface flooding in the city.
Council spokesman Malcolm Hopwood said the city's stormwater system had been unable to cope with the volume of water, and city council work crews had to clear grates and channels of debris and blockages.
Sandbagging was carried out in the Heretaunga Street area near the Little Kawau Stream and in Manuka Street to direct water away from buildings.
There had been some reports of water entering buildings.
In Wanganui roads were closed and sandbags piled up as council and emergency services scrambled to cope with the unexpected downpour.
The deluge overwhelmed the city's stormwater system leaving properties and roads under water.
A section of Heads Rd was closed after water rose to knee height and flooded several industrial businesses.
Mayor Michael Laws told the Wanganui Chronicle the flooding had kept council staff busy until late last night.
Dry ground meant less water was being absorbed by soil, compounding the flooding, he said.
More heavy rain is expected in the area tomorrow and although today it is expected to be dry in many parts of the lower North Island, police were warning misty rain in Wellington and the Wairarapa was making driving conditions treacherous.