Labour says the Government is poised to offer Auckland motorists an election "bribe" by fast-forwarding motorway tunnels under the Waitemata Harbour - without room for trains.

The party's transport spokesman, Phil Twyford, says he has been leaked word that Prime Minister John Key will make an announcement about a roads-only crossing on August 12.

Mr Twyford's claim was dismissed last night by a spokesman for Mr Key, who told the Herald : "The suggestion from Labour that an announcement from the PM is upcoming or imminent about accelerating the second harbour crossing is incorrect."

Fast-tracking the plan would be contrary to a commitment Mr Key made last year that a $4.6 billion set of three-lane tunnels between Takapuna and Spaghetti Junction near Cook St would be "future-proofed" for rail.


Photo / Brett Phibbs, Herald Graphic.

A new harbour crossing was likely to be needed between 2025 and 2030, he said in a major speech which also promised government support for a $2.86 billion rail tunnel between Britomart and Mt Eden.

Mr Twyford, also Labour's spokesman on Auckland issues, said yesterday the Government was planning to bring the harbour crossing forward without a proper economic analysis.

Transport Agency consultants previously calculated that tunnels - then expected to cost up to $5.3 billion - would return just 30c of economic benefit for every dollar invested.

"This Government has made an art-form of using transport projects as pork-barrel politics," Mr Twyford said. "We saw that recently. After starving the regions of transport projects for the last six years, they sprinkle $212 million on regional New Zealand, weeks before an election."

The Transport Agency yesterday announced $458 million of funding to design and construct a 15.5km bypass of Huntly as part of the Waikato Expressway between the Bombay Hills and Cambridge.

A spokesman for Auckland Mayor Len Brown, who wants the tunnels built with provision for train tracks, said he had no comment on "an unsubstantiated leak".

But former North Shore Mayor George Wood, now an Auckland Council member, called for greater planning, regardless of whether the tunnels were brought forward.

"We need it as soon as possible. [But] there's not a lot happening at the moment in relation to the planning. We don't know where exactly the portal is going to be for, say, Onewa Rd and what the traffic configuration's going to be at Esmonde Rd."

The Transport Agency's preferred route for tunnels is between the Northern Motorway south of Esmonde Rd in Takapuna and Cook St on the Auckland side of the harbour. There would also have to be an entry point for traffic from Onewa Rd in Northcote, one of Auckland's busiest arterial routes.

The tunnels would run under Wynyard Quarter, enabling the agency to switch its State Highway 1 designation to the new route for middle- and long-distance traffic, leaving the harbour bridge for vehicles heading between the North Shore and central Auckland.

Although cycling and pedestrian advocates want to build a $31 million tolled pathway under the bridge, Mr Wood says they should wait until a new crossing leaves them with plenty of above-deck space.