A Marlborough crayfishing company is defending its right to drive through a conservation area with a bulldozer to launch a boat.
Burkhart Fisheries says it did not drive on the scientific reserve at Chancet Rocks, but went along the beach as any vehicle is allowed to do.
Burkhart Fisheries was denied permission to launch their boats south of the scientific reserve after the Kaikōura earthquake uplifted the seabed of their original site at Ward Beach.
Forest and Bird regional manager Deb Martin said she was horrified the company took matters into their own hands with a bulldozer and dump truck.
"It's not legally protected to be driven upon, but of course nobody anticipates that somebody's going to take a massive bulldozer and a boat through there.
"When I was there the other day, the birds that would be nesting right now were incredibly distressed and just running up and down in those deep bulldozer furrows," she said.
Forest and Bird was investigating what legal action it could take.
Burkhart Fisheries managing director Dennis Burkhart said the scientific reserve was north of the launch area.
Mr Burkhart said the criticism was unfair, and he was frustrated.
"Yesterday we saw State Highway One open again from Ward to Kaikōura, that's dozens of kilometres of roadworks, much of it alongside the beach and nobody's said boo.
"Yet our efforts to keep doing what we have done for four decades or more and to keep 30 odd local jobs going, just keep gettng hammered."
He denied the company activities were threatening the birdlife.
"If this is any threat to nesting birds, I would have thought - as its the only dog off-leash area in the local area - dogs walking along the zones would have been more of a threat than an occassional dozer going past that's basically driven with care," he said.
"And we've been there all those years and we haven't had any problems with them in the past."
Marlborough District Council said it was aware of the situation and was investigating.