Heavy rain is forecast to hit the top of the South Island as a low-pressure system moves in this evening.
MetService has an orange heavy rain warning in place for Marlborough Sounds, Richmond Range and the Rai Valley from 7pm on Wednesday until Thursday afternoon.
Up to 110 millimetres of rain is expected to fall and people in the area are encouraged to prepare by clearing their drains and gutters and avoiding low-lying areas.
Heavy rain watches have also been issued for parts of Nelson, Tasman, Buller, Wellington, the Kaikoura Coast and Marlborough south of the Richmond Range.
MetService said there was a moderate chance of them being upgraded to warnings.
In the North Island, Taranaki has a severe thunderstorm watch in place from 2am until 11pm on Thursday due to a moist unstable northwesterly flow.
Intense, localised rainfall of 25 to 40mmh is predicted, with the potential for surface or flash flooding.
