It was the gonzo tourism campaign promoting a more literal sort of Down Under.

Now, the Northern Territory's official tourism department has welcomed an advertising standards ruling that the controversial and globally shared "CU in the NT" slogan is obscene and offensive.

The brazen slogan surfaced online in November and was initially incorrectly attributed to the NT tourism department.

Requests for interviews with the still unknown people behind it were met with an automated message apologising that staff were "flat out like a lizard drinking".

As well as Facebook posts describing tourist attractions in the Territory, the group had a sophisticated website where it offered merchandise such as stubby coolers and t-shirts.

'Clever' slogan generated anger

Some people reacting on Facebook called it "clever", while others tagged friends and suggested travelling to the sparse outback region.

"The initial thing about the campaign is that it certainly did get a lot of people talking about the Northern Territory and what there is to see and do up here," said Valerie Smith, acting executive director of the NT tourism department.

But there was also anger at associating the Territory with a swear word describing women's genitalia.

One subsequent complaint to the advertising industry's self-regulated body, Advertising Standards Board (ASB), called the word "denigrating" and argued the campaign was a cheap shot.

The ASB subsequently ruled in favour of the complainant:

"The advertisement had been clearly designed to highlight letters to form a strong reference to the word 'c***'. "The board noted community standards research into language had shown that the community considered the 'C-word' to be obscene and not appropriate in advertising in any form."

Ms Smith agreed.

"While some people might have had a private giggle, it is not something at all appropriate for a marketing campaign.

"It's not something we would do or condone, but at the same time it does hanker to some of that larrikinism that is still up here in the Northern Territory.

Campaign taps into Australia's 'larrikin' reputation

"One of the things that we commonly find when we do research overseas is that something people appreciate around Australians is our open and warm and friendly nature.

"That can sometimes blend into that larrikinism and it can go back to the Paul Hogan and shrimp on the barbie approach.

"But that was all advertising 30 years ago and [we need to] move on from shocking language used in the past."

The ASB has no legal powers, although it has indicated it would approach Facebook to try to have the page taken down.

"I think it's a matter for the ASB to see how far they want to take this," Ms Smith said.

"I think we need to be careful that we don't end up in a situation where everything we think and do is monitored."

The campaign's creators could not be contacted for comment.