Auckland Eastern Transport Corridor recommendation revealed

4.10pm - By MATHEW DEARNALEY

UPDATED REPORT - The recommended options for Auckland's 27km eastern transport loop could end up costing almost $4 billion.

The estimate has ballooned from $460 million in a study two years ago to between $2.8 billion and $3.2 billion -- depending on whether a 3.5km tunnel is built under Hobson Bay at the Auckland City end -- in figures released by Opus International Consulting today.

However, "a worst case scenario" where the costs could rise to between $3.3 billion and $3.9 billion was also acknowledged.

More than 1200 homes could also be bulldozed to make way for the route, but a report by Business and Economic Research Ltd (Berl) says the project will boost employment and urban development for a likely $1 billion to $1.5 billion increase in annual gross domestic product.

Berl is enthusiastic about a possible trenched transport corridor through Glen Innes, stimulating investment in a technology park associated with Auckland University's Tamaki campus.

Opus' recommended option proposes dedicated bus lanes throughout a loop route from Manukau City. They would follow a four-lane motorway for much of the way but separate from it around the Panmure basin.

Another road bridge will be built to the south of the basin, while buses would run to the north.

The consultants have left it to the project partners to choose between an overland motorway route along the existing railway embankment across Hobson Bay to Tamaki Drive, or a tunnel under Parnell to link with the Northwestern motorway in Grafton Gully.

Whichever route is eventually chosen, buses would stay out of any tunnel, and travel across the overland route to the Britomart transport centre.

Possible funding sources were not mentioned in detail, as they will be discussed in a separate report due later this month, but Auckland Mayor John Banks and his Manukau counterpart Sir Barry Curtis are keen on attracting private investors with a promise of tolls.

The Opus report says 30 per cent of the cost will be for buying properties, 30 per cent for public transport and walking-cycling routes, and the balance for motorway building.

An opposition group, Stop The Eastern Motorway, says the project will do little to ease congestion by encouraging more people to use private vehicles despite paying lip-service to public transport.

Spokesman Richard Lewis said it would create an even bigger traffic nightmare in a central Auckland which would be "surrounded by spaghetti junctions."

The mayors, who hope to complete the project within 10 years, say it is essential for Auckland's economic development.

Full map of recommended Eastern Corridor route