The plan to avoid traffic mayhem

The construction gantry towers over the replacement Newmarket Viaduct southbound lanes of the Southern Motorway. Photo / Brett Phibbs

There will be 36 hours of car chaos next weekend when the country's busiest highway closes to south-bound traffic. Eighty thousand vehicles use Auckland's southern motorway, State Highway 1, every Sunday.

But from 5pm on Saturday to 5am Monday, the 2.8km southbound stretch between Gillies Ave and Green Lane East will be closed to allow work on the $215million Newmarket Connection viaduct project.

The New Zealand Transport Agency is pleading with motorists to stay away from central Auckland because of the predicted major traffic jams.

But the NZTA has been criticised for doing the bulk of the work next Sunday - Father's Day - and when there are other big events scheduled in Auckland and the North Shore. "We've copped a lot of flak about our choice of weekend but [were] constrained by dates," said NZTA Auckland state highway manager Tommy Parker.

"We need to close the motorway so we can connect the lanes on the new viaduct with the existing lanes on the motorway. There will be significantly more traffic on local roads than on a usual Sunday. Our key message is, don't travel unless it's necessary."

The closure will involve moving a 140m, 800-tonne steel gantry from the new southbound lanes on to the existing lanes.

The gantry will be moved on rails, with hydraulic ramps used to shift the gantry sideways onto the new lane.

Paving work will then be done at both ends of the bridge to connect it to the existing motorway.

"Moving that amount of steel in [that] amount of time is a very complex task," said Parker.

More than 50 workers will work through the weekend to connect the bridge and manage traffic. The project is expected to cost $300,000 to $400,000.

A team of 20 will move the gantry and a further 30 will manage traffic and finish the paving work.

A team of specialist engineers will be on standby in case moving the gantry creates difficulties. Five traffic engineers will monitor congestion.

On Saturday, North Harbour are scheduled to play Waikato in an NPC match.

On Sunday, Auckland will meet Taranaki at Eden Park and the Silver Ferns will play Australia at Vector Arena.

At this time of year, Father's Day was the easiest date to manage the work, said Parker.

The last time southbound lanes of Auckland's motorway were closed was in 1999 for an Asia-Pacific Economic Co-operation Summit.

Motorway closure labelled 'dumb'

"Pretty dumb" is how Newmarket businesses are describing the decision to close the southern motorway next Sunday.

Father's Day is usually a very good trading day - particularly for bars, cafes and restaurants.

But with huge traffic jams expected and warnings from road authorities to stay away from Newmarket, businesses are predicting a grim day.

" They could have done it on a Sunday when people aren't going out with their families," Urban Cafe owner Johno Evans said.

"It's pretty dumb," he said of the New Zealand Transport Agency's decision.

Newmarket Business Association chief executive Cameron Brewer said it was not a wise choice to close the motorway on Father's Day.

"Putting potentially 20,000 cars through the very small Mortimer Pass on Father's Day is going to create mayhem."

NZTA Auckland state highway manager Tommy Parker said people needed to be patient.

"There will be impacts and we apologise for that. But there's no easy way round it."

Residents are also going to be affected.

David Lam, who lives on Great South Rd, where the bulk of the traffic will be diverted south, said road authorities had been "very slack" in keeping residents informed.

Problem areas

* Great South Rd from Manukau Rd to Green Lane
* Market Rd
* Orakei Rd
* Mountain Rd
* Gillies Ave
* Mortimer Pass
* Broadway/St Marks Rd intersection
* Dominion to Balmoral Rds
* Mt Eden Rd to Balmoral Rd intersection
* Fanshawe St