The Ohai Line, formerly known as the Ohai Industrial Line and previously the Wairio Branch and the Ohai Railway Board's line, is a 54.5 km branch line railway in Southland, New Zealand. It opened in 1882 and is one of two remaining branch lines in Southland, and one of only a few in the country. A number of smaller privately owned railways fanned out from Wairio; one of these lines, to Ohai, was originally built by the Ohai Railway Board and was worked by New Zealand Railways from 1990 and incorporated into the national network in 1992.