The Blue Pools, Rob Roy and Makarora bridges would be closed from today until summer, the Department of Conservation (Doc) said.
The Blue Pools and Rob Roy bridges needed safety upgrades while the Makarora bridge had reached the end of its operational life.
Doc Central Otago operations manager David Butt said while the closures would frustrating for those who wanted to visit the sites, safety concerns were behind the decision.
"These are popular sites that see a high level of visitation, particularly over the summer months.
"Engineering advice is that they cannot sustain the current usage, and with visitor numbers continuing to increase, we need to make them safer."
The Blue Pools and Makarora bridges, both on the popular Blue Pools Track, were visited by about 550 people a day in January, with around 75 people per hour crossing during peak time.
The bridges also provide high-water access to the Young Valley and Gillespie Pass Circuit.
Rob Roy bridge, the only access to the Rob Roy Glacier track, was crossed by about 180 people per day over summer.
"We’ve taken on board expert advice and made the call to close the bridges while we can complete the necessary work.
"It’s not that there is a known fault, it’s the unknown, through heavy use and potential wear and tear that might not be visible. We need to err on the side of caution."
The work was planned to be completed during the summer season, Mr Butt said.
