The harbour bridge's two northbound clip-on lanes are also closed for resealing until Monday morning, meaning the Curran St on-ramp and the Stafford Rd off-ramp in Northcote are also unavailable.
Transport Agency northern highways manager Tommy Parker said the organisation had chosen a time of relatively light traffic for the work, but warned drivers to take care while travelling through a "live" construction site.
"Expect the unexpected," he said.
The agency is trying to prepare drivers for a big change next Monday morning when all four lanes of the Victoria Park motorway flyover become available for southbound traffic.
Northbound traffic was removed from the flyover when two lanes of the tunnel opened in November, and agency contractors have since been working on converting the structure for the exclusive use of vehicles travelling in the opposite direction.
One of the lanes formerly used by northbound traffic has been available to southbound traffic since Tuesday last week, when confusion among motorists led to congestion and queuing back to Esmonde Rd in Takapuna.
That prompted the agency to simplify its overhead electronic message signs.
VICTORIA PARK FLYOVER
This week: Two lanes of southbound traffic only on the flyover. Vehicles turning off the motorway at Cook St or the exits to the port and State Highway 16 must use the left-hand lane.
Northbound traffic uses the new motorway tunnel under Victoria Park.
From next week: Four lanes of southbound traffic on the flyover. Vehicles heading further south must use the two lanes to the right.