Caution is the word for anyone on the roads in western parts of the country

An Orange Heavy Rain warning covers Westland south of Otira until late tomorrow morning, with peak rates of up to 25 millimetres an hour expected.

The warning also covers Motueka, Buller and Westland north of Otira from this evening until late tomorrow afternoon.

MetService meteorologist Alwyn Bakker says streams and rivers could rise rapidly in those areas.

He says flooding and slips are also possible, and drivers are being encouraged to take care or delay travel if possible.