MetService is warning the deluges may cause flooding and slips and make driving conditions hazardous.
As well as rain across much of the North Island a strong wind watch has been issued for Auckland and Great Barrier Island, where gales gusting up to 100 km/h are expected to barrel across the region tomorrow afternoon.
The worst of the rain is expected to inundate the upper half of the North Island tomorrow but the MetService is forecasting some heavy falls are likely to spill over to Thursday when thunderstorms are possible for much of the country.
Meteorologist Tom Adams said the wind was also expected to strengthen to gale-force, tearing through Cook Strait tonight and peaking tomorrow.
Temperatures were expected to remain balmy thanks to a slab of warm tropical air sidling up to the country.