The road has been beset by problems with the sewage system in recent years.
More than 1,000m of pipe from Farlington roundabout to beyond Anchorage Road was relined by Southern Water in May-July 2024 after frequent sewer bursts, leaks and flooding.
The company apologised for inconvenience caused by the latest closures.
“The long-term £2.5m solution will strengthen Portsmouth’s pipeline, using innovative lining technology to futureproof this section of the city’s sewer network for years to come,” it added.