The Department of Conservation planned to build a new bridge, to be ready before the start of the Great Walks season in October, community relations programme manager John Roberts said.
The new structure, costing between $80,000 and $100,000, was likely to have a greater carrying capacity and be more resistant to falling trees and heavy snowfalls.
Mr Roberts said the Routeburn Track from the Glenorchy end would be out of action until the new bridge was completed.
The track was closed last Wednesday when a large snow-laden tree fell on the swingbridge and demolished it beyond repair.
About 43,000 people used the bridge a year.
Doc has also programmed $225,000 worth of upgrades on sections of track totalling 95m, which were uneven, eroded or did not meet the standards of a Great Walk.
About 30m of boardwalk had been laid and the project would be completed by the end of October, depending on weather.
The Routeburn is an average three-day tramp and extends between the head of Lake Wakatipu and State Highway 94, the Te Anau-Milford Road.
One of the department's nine Great Walks, the Routeburn traverses 32km of Mount Aspiring and Fiordland National Parks and is part of Te Wahipounamu South West New Zealand World Heritage Area.
Doc recorded 28,616 bednights and 14,448 people who walked the entire track between October 2006 and April 2007.
Of trampers, 30% were New Zealanders.
