The lane is expected to improve safety and traffic flow.

The changed traffic conditions are expected to be in place from early Friday morning (February 14), but work may be postponed in the event of extreme weather.

"The new lane will allow free-flowing access for northbound motorists from Sparks Road, improving safety and traffic flow by separating them from the northbound M1 lanes until after the Doyalson exit," a spokesperson for Transport for NSW said.

Motorists travelling north from Sparks Road will be able to continue towards Doyalson and Swansea via the existing Doyalson Link Road, or use the new underpass to safely re-join the M1 after the Doyalson interchange to travel to Newcastle.

"Motorists traveling from the service centre southbound will see several small traffic changes in coming weeks as Transport for NSW continues work to finalise the ramps, plant vegetation in the area and complete other minor finishing work," the spokesperson said.

Heavy vehicles should follow road signs and remain in the left lane.

"Speed limits will remain at 80kph for the safety of workers and all road users."

More information about the M1 upgrades can be found at rms.work/M1Upgrades.

"Transport for NSW thanks all road users for their patience during this important work to upgrade this major piece of infrastructure."

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