Auckland Mayoral candidate Phil Goff is promising to prioritise light rail if he is elected.
It is Mr Goff's first firm policy commitment during the election campaign, and comes ahead of the first mayoral candidate debate this evening.
Mr Goff, who is a long-time Labour Party politician and the current MP for Mt Roskill, said light rail would dramatically increase public transport capacity and would reduce pollution because it was electric.
A line from the Wynyard Quarter, up Queen Street, Symonds Street and down Dominion Road was a priority.
However, funding was a major challenge and some form of road charging would be necessary, both to raise revenue and to encourage change of travel modes, Mr Goff said.
He would also be a strong advocate for central government meeting a greater share of the costs growth was imposing on Auckland, he said.