The bridge, which spans the River Forth, was build in 1831
Major work to repair "internal weaknesses" in one of Stirling's oldest bridges is to begin next month.
The B-listed Stevenson Bridge, which carries over 16,500 vehicles a day on the A9, was built to span the Forth by Robert Stevenson in 1831.
Stirling Council said it urgently needed to be repaired having long surpassed its 100-year life expectancy.
Local MSP Bruce Crawford has criticised the timing of the work saying it could impact on the area's tourism industry.
The five-span masonry bridge at Causewayhead serves as a direct route into Stirling from sites like the Wallace Monument and Stirling University.
Mr Crawford said he had written to the council with his concerns.
He added: "I have concerns that the full impact of the partial closure of the Stevenson Bridge will have on our vital tourism industry has not been fully considered.
"The bridge is set to be closed to southbound traffic coming from the Cornton/Causewayhead direction for a prolonged period at the peak of the tourism season, and this could not happen at a less opportune moment as the tourist industry reels from the economic downturn and the recent decision to cancel this year's Stirling Highland Games."
The urgency of the work is being blamed on repeated burst water pipes, buried within the bridge's structure, that have caused deterioration of its sandstone slabs.
Stirling Council said all necessary work to ensure the structure could continue to support the A9 would take "several years".
It added that unless the work was done the bridge would "no longer be able to function fully as a main road".
Councillor Jim Thomson said that although there was "no right time" to carry out the repair work, a drop in traffic volumes because of the school holidays meant June was an opportune time.
He added: "The communities of Cornton, Causewayhead and Bridge of Allan will be most affected by the southbound lane closure.
"However, with the timed warnings of the traffic restrictions, I am sure local people and visitors to the city will make their travel plans fit around the bridge works, allowing themselves extra time to make their journey."
The route will be reduced to one-way northbound traffic for up to seven weeks from 28 June while repair work takes place.
The road will be closed to all southbound traffic from Causewayhead and Cornton with drivers being urged to follow diversions.