Labour MP Phil Goff has promised to make light rail a priority if he wins the Auckland mayoralty.
He said a line from the Wynyard Quarter, up Queen Street, Symonds Street and down Dominion Road is a priority.
Speaking to the Committee for Auckland today, he said the city already suffered from bus congestion and light rail will dramatically increase public transport capacity, adding it was electric and would reduce pollution.
• Auckland mayoral race on the starting blocks
Mr Goff pushed some form of road charging - a petrol tax, tolls or congestion charges - to raise revenue for transport and encourage a change of travel modes.
"I make no apology for making my views clear on that," he said.
"We cannot pretend that there is some magic way of funding infrastructure that doesn't impose any costs on anyone.
"We will need to look in part to private sector options. No funding has been set aside for light rail, for example. Without government funding, a public-private partnership will be necessary if light rail is to finally become a reality."
Auckland Mayoral candidate Mark Thomas rubbished Mr Goff's "enthusiasm for an untested and unfunded light rail system serving central Auckland".
"Throwing support behind undeveloped and unfunded ideas has been a hallmark of Len Brown's mayoralty," Mr Thomas said.
"Aucklanders are still waiting for rail to Albany and rail to the airport the Mayor promised in his first election campaign. Labour's candidate is falling into the same trap."
Mr Thomas said Mr Goff was also confusing his funding options.
"While congestion charging or tolls can have a role to play in a congested transport system - if there are free alternatives - tolling shouldn't be used as 'money grab' to pay for other projects," he said.
The race for the Auckland mayoralty begins this evening at a "meet the candidates" outing organised by the Ellerslie Residents Association.
Six mayoral candidates will be attending - Mr Goff, Victoria Crone, Mark Thomas, Stephen Berry, Penny Bright and David Hay.