Roads through much of Mt Roskill face weeks of congestion while a key motorway link is closed for work associated with the $1.85 billion Waterview connection project.
The Transport Agency intends closing the hillside link between the end of the Southwestern Motorway and Maioro St in New Windsor for four weeks from Friday, July 22, while it builds the first half of a new interchange at the Waterview project's southern gateway.
Maioro St is a busy corridor for Waitakere residents who work in Auckland's eastern or southern zones, including the airport.
The closure will see thousands of drivers jamming local roads in search of alternative passages.
More than 28,700 vehicle trips made over Maioro St each week day will have to be transferred to routes such as Dominion, Richardson, Hillsborough and Stoddard Rds, raising major traffic management challenges for Auckland Transport.
These are already busy and traffic along Hillsborough Rd often reached gridlock before the Mt Roskill motorway extension opened in 2009.
But the Transport Agency intends keeping the motorway and its link with Sandringham Rd open for all except two weekends, when the roundabout marking the end of State Highway 20 will be removed in favour of the new interchange, about 250m to the west.
Northern state highways manager Tommy Parker said the four-week road block would replace an earlier plan for a series of phased closures over 10 to 12 weeks.
It would allow the first half of the new Maioro St interchange to open before the Rugby World Cup, which would have been overlapped by the earlier plan.
Mr Parker said the work was significant and he appealed for support from drivers to ensure the accelerated construction programme could be completed on time.
"Unfortunately this closure will cause delays and we apologise for this.
"We urge motorists to plan ahead, use alternative routes around the city and allow plenty of extra time to get to their destinations on time and safely - especially during the morning and afternoon peaks," he said.
The project will include a half-diamond interchange, two bridges over the motorway and east-facing on and off ramps.
Puketapapa Local Board chairman Richard Barter said he expected mayhem for the first few days of the closure, before drivers settled into alternative routes.
But Mr Barter, whose board represents Mt Roskill, welcomed the Transport Agency's decision to concentrate on a full but shorter closure to ensure the work would not cause extra complications for Rugby World Cup traffic.
Whau Local Board chairman Derek Battersby agreed it was better to have "four weeks of pain than three months of pain".
* From Friday, July 22, the hillside link between the end of the Southwestern Motorway and Maioro St in New Windsor will be closed.
* This is to build the first half of a new interchange at the Waterview project's southern gateway.
* The Mt Roskill motorway extension opened in 2009.
* More than 28, 700 vehicle trips are made over Maioro St each week day.
* The closure means commuters will be using local roads.By Mathew Dearnaley Email Mathew