A West Coast vigilante is thought to be responsible for spray-painting over obscene words on Wicked Campervans as they pass through the region.
Campers staying at the Murchison Riverside Holiday Park have turned up with words greyed out with primer paint.
Holiday park leaseholder Robin Sandford said all of the vans had come from the West Coast, which was where the tourists had noticed the spray paint job.
One first noticed it while outside Westport New World, and another at the swingbridge in the Upper Buller Gorge.
"Good on the West Coast," an amused Mr Sandford said today.
He said the vigilante painter had covered up "what we would call obscenity" on the "really bad" vans.
You could still tell what the message was, but could not read the offending part. He believed they had used a grey primer.
Mr Sandford said he had only received complaints about the vans from a few people, mainly parents of children.
"One guy said his kids were asking 'what's that about?"'
The chief censor recently ruled three slogans on Wicked Campers were R16 and classified them as "objectionable publications".
Further rulings are expected to come. The vans affected by the ban are those carrying slogans which linked drug use to children. One carried an image of Snow White using what appeared to be a crack cocaine pipe while another featured cartoon characters Scooby Doo and Shaggy smoking marijuana.
The third van to have its slogan banned showed a Dr Seuss character also talking about smoking marijuana; words on the van attributed to the character were "I did a bong, I did, I did".
Mr Sandford said he received far more complaints about freedom camping. Even freedom campers turned up at his campground, and told him they could not camp out that night as there was too much toilet matter left from other freedom campers.
"I have people complain almost every day."