The famous graffiti on Katherine's Railway Bridge — declaring the favourite snack of a religious figure — has been officially trademarked.

Toni Tapp Coutts has trademarked a famous piece of graffiti. ( ABC )

Author and Katherine town councillor Toni Tapp Coutts spent eight months and "quite a bit of money" trademarking the "Jesus loves nachos" slogan, and hopes it could eventually be used to promote tourism to the region.

That would put it among a growing list of off-the-wall Territory tourism campaigns, including the Crocodile Dundee teaser launched at the Superbowl, and the cheeky C U in the NT slogan.

But for short-term she would sell tea towels and screen-printed t-shirts bearing the words.

"It's just a beautiful piece of quirkiness," Mrs Tapp Coutts said.

"I want to keep the story alive and give it its own little piece in the world. Because it's fading, you can barely see it now and somehow I'd like to get it repainted back onto the bridge."

But despite the popularity of the slogan, Mrs Tapp Coutts said not all Katherine residents shared her passion.

"There's lovers and haters of it in Katherine," she said.

"I've got some friends, Catholic older ladies, who aren't happy about it but as they say, they don't lose sleep over it," she said.

Although the story of the graffiti's origins remains a mystery to most of the public, it is believed a member of the Tapp family was involved.

Speaking to ABC Darwin on Tuesday, Mrs Tapp Coutts would only confirm it was painted by a member of her family, but wouldn't reveal who.

Asked if she would split the royalties with this original artist, she replied "depends on how many champagnes we have while we're discussing it".