Emergency management teams are watching the sky on West Coast

MetService have issued an Orange Heavy Rain Warning and a Severe Thunderstorm Watch for Westland.

Up to 300 millimetres of rain could fall in the ranges between Otira and Bruce Bay - up to 150 everywhere else.

Civil Defence Group Manager Claire Brown says the amounts forecast could have an impact across the southern parts of the region in particular.

She says it's important people take the necessary precautions as required.