Repairs will slow airport traffic

Both northbound motorway lanes across Mangere Bridge in Auckland will be closed for most of the next eight weekends - starting late tonight - for the replacement of six heavy expansion joints.

The lanes will be closed from 11pm tonight until 5.30am on Monday, to all except emergency vehicles and buses, leaving other traffic to face lengthy detours around the Manukau Harbour to reach Auckland from the airport.

Buses will be granted special access for most of the time, except for tomorrow, when safety considerations mean they must use detour routes.

One suggested route, running anticlockwise around the harbour to Onehunga via Otahuhu, will add about 10km to journeys to the northwest - or about $23 to taxi fares.

Another exception will be the weekend of March 17 to 20, when all lanes will be kept open to allow relatively unimpeded access to the two sell-out U2 concerts at Ericsson Stadium.

Airport chief executive Don Huse said that although inconvenience to travellers and staff was unfortunate, he accepted the need to replace the bridge joints and was pleased Transit New Zealand intended keeping the structure open to southbound traffic heading his way.

This meant passengers would not be diverted on their way to catch flights, although Transit says they could still face some delays so should allow extra time to reach the airport.

"As a major infrastructure provider ourselves, we understand how critical it is to undertake necessary maintenance," Mr Huse said.

Opus Consultants network operations manager Dave Ashby, whose organisation is the main repair contractor, said last night the new joints were needed to replace those that had served the bridge since it opened about 25 years ago.

Weighing at least two tonnes each, and costing more than $2 million to install, they would also shore up the bridge's ability to withstand earthquakes.

Engineering teams from Australia and from the German suppliers of the joints would be on hand during the project.