The Hotspot Watch issued by Niwa this week says Masterton has the driest soils in New Zealand compared to normal for this time of year.
Despite the weather bomb across the North Island earlier this week, Wairarapa's soils remain below normal for soil moisture.
Soil-moisture levels compared with this time last week have increased only slightly in Wellington and Wairarapa.
Niwa said the driest soils in the country were in Masterton and north-eastern Gisborne.
Sunday and Monday are expected to be mainly dry across the North Island.