York Road in Waterloo will be closed to northbound traffic for around a week from 9pm on Tuesday while SGN carry out emergency gas repairs.
"To ensure everyone's safety, the northbound lane between Chicheley Street and Mepham Street will be temporarily closed from 9pm tonight for approximately one week," an SGN spokesman told the SE1 website.
"We're aware this is a busy route and will be working hard to complete this essential work as quickly as possible.
"We'd like to apologise to local residents and motorists for any inconvenience caused."
For the latest local news and events direct to your inbox every Monday, you need our weekly email newsletter SE1 Direct.
7,000+ locals read it every week. Can you afford to miss out?
Read the latest issue before signing up