The changes came after a ministerial inquiry into the existing laws, on the back of an increasing outcry about rules being flouted.
Conservationists, iwi and political parties have been vocal for years about habitats being destroyed by "swamp kauri cowboys", and the flow of raw millable timber exported under the guise of "stumps" or "artworks".
They have also accused NRC of "rubber-stamping" the destruction of wetlands that would be protected elsewhere in New Zealand.
Fiona Furrell, from the Northland Environmental Protection Society, said the changes did not address kauri passing through export loopholes.
"We need a law change to be explicit. That means ending the export of fake 'temple poles', dodgy 'Maori carvings', 'slabs' and 'stumplogs' as finished products," Ms Furrell said.
The region's politicians have also panned Mr Guy's changes, although they admit Northland's economy could benefit from a properly regulated, environmentally safe swamp kauri industry.
Northland MP Winston Peters (NZ First) has invited Mr Guy to slide his rear end along the rough-hewn slabs being called tabletops for export purposes.
"He, not the slabs, would be finished," Mr Peters said.
Te Tai Tokerau MP Kelvin Davis (Labour) said the change "won't make an iota of difference".