The export of kauri logs as Maori carvings is very closely monitored and is not being used as a way around the law, Primary Industries Minister Nathan Guy says.
Northland conservationists have made complaints that large logs are being dug out of wetlands and then being sold overseas.
The ecologically-sensitive wetlands are badly damaged in the process, the Far North Protection Society say.
Swamp kauri can be exported without Ministry of Forestry (MAF) approval if it is a finished or manufactured product, or a personal effect.
Whole or sawn salvaged swamp kauri stumps or roots can be exported with a MAF milling statement and export approval.
Swamp kauri logs may not be exported, either whole or sawn. But with swamp kauri fetching large sums overseas, particularly in China, the society says logs were being cynically passed off as Maori carvings and then sent out of the country.
They have complained that the Ministry of Primary Industries (MPI) and Customs have turned a blind eye to the loophole.
"The logs are just logs, with a few scratchings on them," the group's chair Fiona Furrell told Radio New Zealand.
"They're less than 10 centimetres deep because the prime object is the log, so you don't want to damage the timber, because the value of the log on export is in the timber, not in the carving."
Mr Guy said he was aware of the group's concerns. Such exports needed to be signed-off as finished products by MPI and Assure Quality.
"I have seen some photos where some fantastic looking kauri swamp logs have been carved and they are going to be an amazing feature for our country in an international country that they are destined for. So we manage it very, very closely," Mr Guy said.
"Officials take a very close interest in this. We have been processing kauri logs from swamp for about 30 years domestically, the export market has grown.
"MPI are watching this space very, very closely, they are satisfied that is working as they anticipated it would."