West Coasters are being warned to watch the skies, with a seriously wet Monday on its way.

Government meteorologists have issued a severe weather warning for the Westland ranges.

It says up to 150 millimetres of rain could fall from early tomorrow until late on Tuesday.

A watch is also in place for Fiordland.

Forecasters say while heavy rain isn’t unusual for the areas, rivers and streams are likely to rise rapidly and there’s a chance of surface flooding.

– Newstalk ZB