Shifting the Port of Auckland to Marsden Point in Northland is a "dumb idea" and some of the other alternative sites being suggested aren't much better, according to the head of the country's biggest transport firm.
A feasibility study of such a move was one of the concessions won by New Zealand First in its coalition deal with Labour.
But the managing director of Mainfreight, Don Braid, said relocating the port didn't make sense.
"I think it's dumb to be quite honest, the rail network couldn't cope, and I don't think there's too much thought gone in to whether that can work or not."
The port is the second biggest in the country, but attempts to enlarge its wharves into the harbour have attracted strong opposition. The port company, which is totally owned by the Auckland Council, earlier this month issued a 30 year master plan on how it might operate ahead of a possible relocation.
Mr Braid said he wasn't sure the port needed to be moved at all.
"I think we can run a very efficient port here alongside the requirements of the city needing the harbour by the use of rail and inland ports."
"I'm sure that the port that we've got here would do a very good job. To move the port to some of the suggested locations just doesn't make sense to us," he said.
An independent study produced for the council last year suggested the Firth of Thames or Manukau Harbour as the best alternative sites for the port.
Mr Braid said the new Labour-led government was making the right noises about investing in infrastructure, in particular about boosting KiwiRail, although he had doubts about the scrapping of the proposed East-West link motorway.