The South Australian Labor Party says a campervan emblazoned with a slogan about masturbation is proof laws need to be passed to crack down on offensive vehicles.

Key points: It was ruled last month that the campervan had breached the code of ethics

It was ruled last month that the campervan had breached the code of ethics Complainants say the text is "wildly inappropriate in a public setting"

Complainants say the text is "wildly inappropriate in a public setting" State Transport Minister says Labor's bill will not solve the problem

An Opposition bill before Parliament targets companies like Wicked Campers, and would allow authorities to deregister vehicles if a company failed to act on rulings by the Advertising Standards Bureau (ASB).

Last month, the bureau ruled a Wicked van registered in South Australia had breached the advertising industry's code of ethics, but nothing has been done to remove it from the road.

The van carried the text "Masturbation is the only thing that isn't taxed, regulated or illegal".

Wicked Camper vans with offensive slogans can be found all across the country. ( ABC News: Casey Briggs )

"That's your freedom; you're free to go f*** yourself," the van read.

Complainants told the ASB they were offended by the content and language.

"It has overt sexual references that would be difficult to explain to children," one complaint said.

"Wildly inappropriate in a public setting … I still can't believe I saw it really."

The van was found to have breached the industry's code of ethics section about avoiding "strong or obscene language".

Wicked Campers did not respond to the complaint or the ASB's determination, and the ASB said it would continue to work with authorities regarding the issue of non-compliance.

'Utterly unacceptable': Opposition

Katrine Hildyard, Labor's spokesperson for the status of women, said this case demonstrated why authorities needed greater powers.

She called on the State Government to support her bill, which she introduced to Parliament last year.

"It's shameful that they have adjourned the bill on multiple occasions," Ms Hildyard said.

Transport Minister Stephan Knoll says Labor's bill will not solve the problem. ( ABC News: Nick Harmsen )

"The slogans on the Wicked campervans promote and traverse violence against women, sexism, racism, paedophilia, and they are utterly unacceptable."

Labor's bill mirrors laws already in place in Queensland, Tasmania and the ACT.

Transport Minister Stephan Knoll has previously argued the law would not be effective without a nationally coordinated approach, as Wicked could simply re-register its vehicles in another state not covered by the rules.

A South Australian-registered Wicked campervan sparked offence in Queensland last November but could not be taken off the road because it was registered interstate.

Mr Knoll said Labor's bill would simply not solve the problem.

"The Liberal Government is interested in solutions that will deliver real outcomes and is currently working towards that," he said.

'We don't condone these messages'

But Women's Legal Service SA said it would still be a hugely symbolic statement by South Australia.

Laws are already in place in Queensland, Tasmania and the ACT. ( Flick: Shellie Evans )

"We don't condone these kinds of messages … I don't think anyone can argue against what this piece of legislation is trying to do," the service's chief executive Zita Ngor said.

"If we stand with those states and territories … it's only going to be a matter of time before other states and territories get on board."

The legal service is one of a coalition of groups which have signed onto a joint statement in support of change.

The statement is coordinated by the Coalition of Women's Domestic Services, which represents most domestic violence services in the state.

"Passing this legislation will ensure our leaders send a clear message to our South Australian community about what our Government and our Parliament values," the open letter reads.