Waitaki District Council community services group manager Thunes Cloete said the bridge was the last part of the Enfield off-road section to be completed.
The on-road section of the 312km Alps 2 Ocean (A20) cycle trail, between Aoraki/Mt Cook and Oamaru, opened in February 2013.
Off-road sections were still being developed.
A spokesman for Recreation Construction, the company that installed the bridge, Clint O'Brien, said preparing the old railway embankment for the bridge took about a month.
He said the site was on a former railway line used the 1950s.
Tourism Waitaki general manager Jason Gaskill said the Enfield segment was one of the main connections in the off-road trail between Duntroon and Oamaru.
He hoped most of the off-road segments of the trail would be completed within the next 18 months.
