Works in Poulters Lane, set to start on September 5, will replace 125 metres of metal gas mains with modern plastic piping.
SGN, which obtained a permit for the improvements from the county council, are expected to remain on site until December 2.
Construction manager Steve Colvin said: “We understand that people can get frustrated by roadworks. However, the new plastic pipe has a minimum lifespan of 80 years.
“This means that when the work is complete, Worthing residents will continue to enjoy the benefits of a safe and reliable gas supply for years to come.”
Work will be carried out in three phases, upgrading individual service pipes to all properties in the road, as well as the main gas pipe.
Engineers will progress westwards along Poulters Lane, between South Farm Road and Offington Lane. The road will be closed for the duration of the works.
Diversion routes north – using Offington Lane, Warren Road and South Farm Road – or south via Rectory Road, Tarring Road and Broadwater Road, will be signposted.
Access for residents and emergency vehicles will be maintained.
Mr Colvin added: “We will be doing everything we can to minimise disruption during our essential project.
“We will be working extended hours, seven days a week, to complete the work as quickly and safely as possible. We are mindful of those people who live along Poulters Lane and will try to minimise noisy activities at evenings and weekends where possible.”