Police were notified in the early hours of this morning, and search is currently under way.
Around 15 LandSAR, Police Search and Rescue, and Amateur Radio Emergency Communications volunteers are involved in the search.
"The weather has been mild, however there is concern for the man having been out overnight," Southland Area Commander, Inspector Joel Lamb said.
"We're appealing for anyone who may have seen the man, who is Maori, in his 40s, solidly built, and who was dressed in shorts, a T-shirt, and hunting boots, to contact us."
Any information can be given to Southland Police on 03 211 0400.