National Grid is upgrading nearly a kilometre of gas mains in the streets around Lincoln Cathedral and The Strait.
Work started on January 5 and is expected to take until the end of March.
The existing iron gas mains will be replaced with tough plastic pipes that have a lifespan of at least 80 years.
Mains are scheduled to be replaced in Garmston Street, St Martin’s Street, Well Lane, The Strait, High Street, Corporation Street and Minster Yard.
Work started on Garmston Street on January 5. From January 5 -19 some parking bays will also be suspended to facilitate the work.
Well Lane work will start on January 12 and is expected to take until January 31. Well Lane will be closed to traffic however pedestrian access will be maintained.
Upgrade work will then begin on St Martin’s Street on January 26 and is expected to take until February 14. Again the area will be closed to vehicles but open still to pedestrians.
National Grid authorising engineer Paul Martin said: “This is essential work that will ensure local residents and businesses can continue to enjoy a safe and reliable gas supply.
“We will make every effort to minimise any disruption caused by our work. The work has been scheduled to avoid the busiest times for the area, such as Christmas, and great care will be taken to restore cobbles, paving and other road surfaces.”