Export NZ is demanding to know how all exporters will be affected by shipping changes dairy giant Fonterra is contemplating.
The country's biggest exporter is reviewing its ocean freight services, on which it spends hundreds of millions of dollars a year.
Any changes it makes to the pattern, frequency and
charges of ship calls will affect other exporters.
Export NZ chief executive Bob Walters said the country had to be careful that it did not let one party make a short-term gain at the expense of others.
"If one player wipes out a significant competitive advantage for others, is that in the best interests of New Zealand Inc?"
Fonterra's review of ocean freight follows a detailed study of land-based arrangements that identified savings by setting up a new warehouse and freight hub in Hamilton to handle its dry goods exports.
This site will be connected to rail and is almost the same distance from Auckland as it is from Tauranga.
It is not known which port Fonterra will use to move dry goods produced in the Waikato.
Ship calls could shift from Tauranga to Auckland or vice versa.
Walters said there could be fewer ship calls to the South Island if big hub ports developed in the north.
Feeder services to hub ports would increase costs.
One of the aims of the Fonterra exercise is to reduce the costly movement of empty containers around the country.
"I don't think it is fair to ask Fonterra to be mindful of other people, but I do think it is fair to ask Government's development agency to look at how it will affect New Zealand," said Walters.
He wants Trade and Enterprise New Zealand or an independent outside consultant to study the likely impact on other exporters of Fonterra's logistics changes.
