Cornwall's capital city is facing a “perfect storm” of road closures and new traffic schemes in January.
Sewerage and gas works will cause a substantial section of the city centre to be closed to traffic for months.
At the same time new traffic lights on Morlaix Avenue will come into operation marking the completion of the Trafalgar roundabout scheme.
Rob Nolan, councillor for Truro City Council and Cornwall Council, said: “It’s a perfect storm for businesses in Truro. It’s all too much for Truro all at the same time.”
Mr Nolan said it did make some sense to have the work carried out at the same time but was concerned about the impact on businesses at a difficult time of year.
The £3.5 million South West Water scheme to improve sewer works started in September last year but was halted over Christmas after pressure from traders.
Road closure orders are in place from MondayJan6 for Kenwyn Street and Little Castle Street until the end of June and in Frances Street and Edward Street until the end of March.
Wales and West Utilities (WWU) is carrying out a £425,000 scheme to replace more than 1km of gas main that means King Street, High Cross and St Mary’s Street will all be closed until the end of March.
The new traffic lights on Morlaix Avenue have been put in place to allow buses to turn right into Quay Street and are expected to be switched on for Monday morningJan6.
WWU said its work, which also started in September last year, was “essential for the safety and security of gas supplies to people and businesses in the area”.
Paul Trevaskis, WWU project manager, said businesses had been informed that deliveries would be accommodated and signs would show that all businesses are open.
He said: “We appreciate that work of this kind is disruptive, and I would like to take this opportunity to thank the local community for their patience whilst this essential work is completed.”
Neil Scott, Truro’s Business Improvement District manager, said: “Nobody would expect the extensive programme of essential gas works that have been taking place in the centre of Truro over the past two months to be without disruption but I have been impressed with the level and regularity of communication from the project team.”