Two planned four-week closures of Lawrence Hargrave Drive have the potential to cause huge traffic headaches for the northern suburbs.
Roads and Maritime Services is looking to carry out work to reduce the risk of land slips along Lawrence Hargrave Drive at Stanwell Park.
The work would see the full closure of Lawrence Hargrave Drive in both directions for 1.3-kilometres between Otford Road near Bald Hill and Chellow Dene Avenue.
The work will be carried out in two stages, with two four-week closures.
The first four-week closure is proposed during February-March 2020 and the second during May-June 2020.
Detours will be via Bulli Pass and the M1 Princes Motorway, which means anyone living south of the road closure and wanting to go to Sydney will need to travel down Lawrence Hargrave Drive and use Bulli Pass.
With residents complaining about the congestion that road is already experiencing, the closures could funnel even more traffic through the Thirroul area.
"Around 4500 vehicles use this section of Lawrence Hargrave Drive each day and motorists may notice some additional congestion on the Princes Highway and Lawrence Hargrave Drive during peak times," a Roads and Maritime Services spokeswoman said.
However, the closure could also stop daytrippers from travelling to the Illawarra.
A Roads and Maritime Services spokeswoman said a full closure was the only option due to the narrow and winding nature of the road.
READ MORE: Dapto drivers still angry about APR bypass
"The road at this location is narrow and work involves using large machinery and drilling equipment which doesn't leave enough room for vehicles, pedestrians or cyclists to pass safely," the spokeswoman said.
The hours it would take to remove heavy equipment made it impossible to open Lawrence Hargrave Drive during peak periods.
An online FAQ states that in the event of an emergency, "the road could be reopened in a matter of hours".
Roads and Maritime Services is calling for public feedback to help reduce any impact of the closures on the northern suburbs community.
"This feedback will help us to determine the time-frame for this work and to alert us to any issues or concerns the community may have," the spokeswoman said.
"We will use this information to help minimise the impact of the work as much as possible."
Extra bus or train services during the closures are also being considered.
Exploratory work had identified several areas along the stretch of Lawrence Hargrave Drive that were at risk of land slip.
The work to be carried out will include installing mesh and soil 'nails' - steel bars up to 13 metres long - to reinforce the ground and building a concrete retaining wall.
The road surface will also be repaired and guardrails replaced.
People can give feedback online at rms.work/lhd-closure.