Starting on Monday May 23, single lane closures will be enforced in Bath Street and Spencer Street, with multiway traffic lights in place for about five weeks.
The works will then pause for eight weeks while the Commonwealth Games comes to town.
After that, single lane closures will then be enforced in Russell Terrace and Willes Road, with multiway traffic lights in place for about four weeks.
The road closures will allow workers to reinforce the gas supply to Leamington.
A spokesperson for Cadent Gas Limited said: "Following recent growth and development in the area it has become necessary to reinforce the town’s supply by adding a new gas pipe to the network.
"The new pipe will be made of a tough plastic material that will help get the local network ready to start carrying green gases like hydrogen, which is vital for a ‘net zero’ future.
"To minimise disruption, the work will be completed in two phases, pausing so that the Regency town can play host to the 2022 Commonwealth Games.
Gary Powell, contract support manager at Cadent, said: “We need to install the new main to keep gas flowing safely and reliably, so that local homes can use it for central heating, hot water and for cooking.
“We would like to thank people for their patience while the work is carried out. Every effort will be made to complete this project as soon as possible.”