MetService has released a severe weather watch for the Bay of Plenty.

In the Bay, where conditions have become saturated over recent rainy days, MetService said 20 to 40mm of rain could accumulate during Sunday.

However, with the risk of thunderstorms there was the possibility that rainfall accumulations would be higher in localised places - possibly 40-60mm.

This amount of rain could make the already saturation conditions worse, causing rivers and streams to rise further and possible surface floods and slips.