Auckland Transport's strategy and planning general manager Pete Clark suggested yesterday that light rail could be extended in the longer term to Botany, North Shore and alongside the Northwestern Motorway.
The organisation's chairman, Lester Levy, emphasised last night that the city rail project remained top priority, and trams would not be in competition with trains, which would remain the fastest way of moving the greatest number of people.
"But if all we have on certain routes is just a row of buses going nowhere, that's no solution," he said, noting that trams could carry three times as many people an hour.
Even double-decker buses, which Auckland Transport is also looking at, would only "buy a little bit of time".
Auckland Mayor Len Brown, who is today unveiling a 10-year budget with deep cuts to transport spending unless he can convince the public to accept motorway tolls or higher rates, said trams were not a priority for him although he would be interested in the outcome of the investigation by Auckland Transport.
"There's no funding, nothing in the timetable, no decisions made - just an interesting opportunity for an investigation so I will be measuring this work beside all the other work that is presently unfunded in the budget."
But Dr Levy disclosed Auckland Transport was considering "a novel form of financing" involving private investment to shield the council from any extra burden for at least the first five years of light rail.
He hoped for "a complete case" to be ready for his board to approve in March, before referring it to the council and the Government in time for inclusion in the city's long-term plan.
He said many overseas cities were turning to light rail as technological improvements brought costs down and removed the need for overhead wires.
Former Auckland City Mayor Christine Fletcher, who championed light rail up Queen St, was "elated" council policy staff were recognising trams as "a critical solution".
