New Zealand shipping businesses are calling on politicians to consider maritime when looking at transport options for freight.
The New Zealand Shipping Federation has released a document called Full Steam Ahead, encouraging politicians to appreciate the advantages of maritime transport.
Executive director Annabel Young said shipping tended to get left out of discussions when the government planned new transport developments.
"If you are looking at transport, we think you need to look at road, rail and maritime to get a full sense of the costs and benefits. If you are ignoring the maritime option, you really are looking at transport as though it is a three-legged stool with one of the legs missing."
Ms Young said using ships for moving freight throughout the country would reduce greenhouse gas emissions and make roads safer by getting more trucks off the highways.
There would also be cost advantages, because roads and railways had to be paid for and were often expensive.
As well, federation figures showed shipping was best in terms of greenhouse gas emissions; shipping emitted 8-15gm of carbon dioxide equivalent for every tonne of freight carried for 1km, while rail emitted 20-25gm and road travel 90-120gm.