"We just have a low pressure system that's sort of mainly out over the Tasman and it's bringing down a lot of moisture from the northwest and swinging it around on to the east coast, and that low pressure systems sticks around well into the week."
MetService also said that on Wednesday and early Thursday, there was a moderate risk of warnable amounts of rain in Hawke's Bay and Gisborne.
The forecast rain will top off a slightly damp month for Hawke's Bay.
Since the start of the month Napier has seen 41.8mm of rain, while things have been even wetter in southern Hawke's Bay - so far this month, Dannevirke has recorded 51mm of rain.