Transport Agency officials are closing the road to Milford Sound as a precaution against motorists being affected by forecast heavy rain.
MetService is predicting up to 250 millimetres of rain in Fiordland in the 24 hours to 9pm on Wednesday,as well as on the main divide and the headwaters of Otago and Canterbury rivers and lakes.
The Milford road, State Highway 94, has been closing between the Homer Tunnel and Murrell's Bridge each night from 7pm since the end of November because of the risk of rockfalls.
But the agency says the road will stay closed all day tomorrow and until Thursday morning until the rain burst passes.
The agency says it is working closely with local tourist operators to minimise the impact of the closures, but public safety is its top priority.