Is Winston Peters' Ports of Auckland plan even possible?

One of New Zealand First leader Winston Peters' bottom lines is moving Auckland's port to Northland - but is that even possible?

Ports of Auckland is owned by the Auckland Council. It sits on prime waterfront land, and for years many in the city have wanted it gone.

However while it might be considered an eyesore by many - it's also a cash cow. It makes ratepayers tens of millions of dollars every year.

But could Mr Peters force any new Government to tell the council-owned company to shut up shop and move?

It would certainly be a huge and expensive undertaking.

The sheer size of Auckland's port - 77 hectares - dwarfs North-Port in Whangarei.

Building the new infrastructure needed, such as cranes and terminals would be massive.

But replicating the three kilometres of berth space Auckland has would prove even more difficult and take up much of Whangarei harbour.

The move would also require a huge upgrade of rail lines between Northland and Auckland, costing more than half-a-billion-dollars.

Mr Peters says it's all worth it to bring jobs back to the North to revive its struggling economy.

While Auckland's mayor is keen for the port to go, he's not so keen to see the money it brings to the city go with it.

"Ratepaters get $60 million in dividends a year from the operation of the ports of Auckland so our first preference would be to retain the Ports of Auckland not in the CBD but in the Auckland region," says Auckland Mayor Phil Goff.

A study on the future of the port found the best place to move it would actually be the Manukau Harbour or the Firth of Thames. That would cost the council $4 to $5.5 billion. It's predicted any new government that wants to move it north would have to fork out the same.

And it wouldn't happen anytime soon.

"This would be a major undertaking," says shipping industry commentator Dave Macintyre. "If you could do it in ten years I think that would optimistic."

We will soon know how optimistic Mr Peters really is about a shift North.