"Motorists planning to use the Northwestern Motorway should factor extra time into their journeys as they will need to follow the detour route through Great North Road, Rosebank Road and Patiki Road before re-joining the motorway."
All lanes heading towards the city will stay open throughout the weekend, along with the Rosebank Road on-ramp and the Northwestern Cycleway.
Those motorists wanting to travel to Te Atatu should continue down Ash Road rather than re-join the motorway at Patiki Road.
If the weather is bad the work will be rescheduled to the following weekend, 23 and 24 July.