MetService has issued a severe weather warning with damaging winds forecast for inland Southland and heavy rain in Fiordland.
Severe north-westerly gales are predicted to develop overnight and last through most of tomorrow.
Emergency Management Southland is urging residents and businesses in inland Southland to check all property is secure.
"Take your outdoor furniture inside and check for loose roofing iron or tiles," Manager Neil Cruickshank said.
Met Service says the gales could bring gusts of up to 130km/hr, which have the potential to damage trees and insecure structure, bring down power lines, and make outdoor activities hazardous.
It was also a good idea for householders to check that they had torches and spare batteries, and a battery-powered radio in case of power cuts, Cruickshank said.
"If the gales develop at the strength MetService is forecasting, it will be dangerous to be outside with flying debris in the air and trees or branches falling across roads. Be prepared to delay travel plans on Friday morning if the winds are still dangerous."
Cruickshank said his staff had alerted Tour of Southland organisers to the severe weather warning.
The forecast for Fiordland is predicting intense rain from today until tomorrow night with 200-250mm of rain likely. The most intense falls are forecast for tomorrow, with rates of 20-30mm/hour.