Court costs and battle fatigue could force a Northland environmental group into recess after losing its fourth case fighting for tighter regulation of the swamp kauri trade.

The Northland Environmental Protection Society is buckling under the weight of more than $20,000 in court costs, awarded against it by the Appeal Court, but while it has lost every court battle, president Fiona Furrell believes it has won the war by keeping helping inform public opinion.

"I believe we have punched above our weight," she said.

Read more: Swamp kauri court case could sink Northland enviro group


"This case might be the last thing we do, but, as a very small group with few resources, I feel we've achieved some good." Ms Furrell said the group was grateful to Auckland law firm Lee Salmon Long who took the appeal case.

The Court of Appeal has found in support of a High Court ruling upholding the Ministry for Primary Industries' interpretation of the Forest Act, which allows the extraction, sale and export of swamp kauri and other indigenous timbers. But the NEPS is vowing to make a loud call for an overhaul of the Forest Act 1949.

Ms Furrell said the courts' judgments were based on interpretation of the current laws, but it was time the Government rewrote the act.

"We've had excellent support from Winston Peters and NZ First over the years, and now that Eugenie Sage, from the Greens, is the Conservation Minister, something might be done," she said.

The Forest Act had been "deliberately" left outside the Resource Management Act, meaning only the MPI had governance over it, she added. The rules were tightened in 2015, but the society took the ministry to court twice last year, saying kauri stumps were being passed off as artworks and furniture in breach of the Protected Objects Act and the Forest Act.

It was also concerned about the destruction of wetlands, wildlife and plant habitats during excavation.

A renewed Forest Act needed to encompass other conservation programmes, Ms Furrell said. That was urgent when kauri die-back was spreading yet living kauri were still being felled in Northland.

Minister of Forestry Shane Jones said the government intended reviewing all aspects of exotic and indigenous forestry, including the Forest Act.

"The Prime Minister has made it quite clear she wants a review of our forestry that includes all timber strategies. We fully intend looking at what other things we can do better in the broader indigenous forestry space," he said.