Auckland mayoral candidate Phil Goff is pushing for the Ports of Auckland to be shifted, telling The Nation programme that by the time the port reaches capacity, it'll be too late to make a change.

While Manukau, Muriwai and the Firth of Thames have all been floated as possible future sites for the port.

Valuable land in the CBD is being wasted on used cars and containers coming into the country, Mr Goff argues, and in only three to 12 years room is going to run out.

"What you can do as an interim is that you can move the used cars off the wharves in Auckland and you could put them in Northport."

And it'll cost less than the estimated $5 billion to shift the port.

"The chief executive of Northport has told me that he can deliver the cars to the consumer in Auckland for the same price as they get it from those cars sitting on really expensive real estate," Mr Goff tells The Nation.

A report by Ernst & Young examining the future of Auckland Port is due in the next few weeks but Mr Goff isn't confident it will have a definitive answer as to the port's final location.

But whatever else, further expansion into the Waitemata Harbour is out of the question.

"My position's very clear," Mr Goff says. "We have to preserve our harbour. We've got to restore access to the harbour by the public.

"I don't think we should be reclaiming any more of our harbour. The thing we should be reclaiming is public access to our harbour, which we've lost over the past 100 years."

Newshub.