West Coast motorists are being urged to take it easy when driving along SH6 late night tonight.

A heavy rain warning is in place as of midnight.

Up to 500 mm could fall between Ross and Bruce Bay in South Westland and south of Arthur’s Pass from the early hours of Wednesday into Thursday MetService said.

Waka Kotahi Journey Manager Tresca Forrester said “this can make driving hazardous and lead to localised slips and surface flooding.

The headwaters of the Canterbury and Otago lakes and rivers may catch the rain with streams rising fast.

“Please check the MetService warnings if you are driving along SH6 or in Fiordland and the Waka Kotahi highways page for any advice or closures.”