The Ministry for Primary Industries has agreed an American importer of swamp kauri was wrong about the size of timber that can be legally exported.
Robert Teisberg of Wisconsin last week told Radio New Zealand that stump kauri can be exported as long as the slabs are no longer than the circumference of the tree.
His comments were then endorsed by a ministry spokeswoman, who said she was comforted by the American's knowledge of New Zealand law.
The ministry now says Mr Teisburg got it wrong: exported stump timber must be no longer than the diameter of the trunk.
That is about three times shorter.
However, the ministry said it was satisfied the timber Mr Teisberg has imported complied with the Forests Act.