"This is an outright win," NEPS president Fiona Furrell said, adding that the ruling applied to all native timber.
The Forests Act defines a manufactured product as one leaving New Zealand "without the need for further machining or other modification", the court saying the product must be ready to be used or installed in the form in which it was to be exported.
Logs would "almost always require modification before being ready for use or installation. Merely labelling a log a totem or temple pole does not change this," it added.
The Forests Act generally requires value to be added in New Zealand after milling before swamp kauri can be exported.
NEPS' argument in relation to the cultural, artistic, social and historical significance of swamp kauri in terms of the Protected Objects Act was largely related to its significance of as a finite resource and its essential character.
"We do ... accept that swamp kauri is a finite resource, and that it has scientific and cultural significance. Its significance is heightened by the threat to living trees from kauri die-back disease," the court ruling added.
It also acknowledged that the society's purposes included protection of indigenous biodiversity ecosystems in Northland, but noted that there were no controls on the extraction of swamp kauri in the Forests Act, although extraction might be subject to other legislation, such as the Resource Management Act.
Ms Furrell said NEPS' focus would now turn to the Northland Regional and district councils' policies. "We now intend to investigate the role our councils played in this mess," she said.