Signage on Darwin buses warning passengers they may be removed for wearing stained clothing has been slammed by an Indigenous health organisation, calling it a punitive response which targets the Territory's most vulnerable.

The Aboriginal Medical Services Alliance Northern Territory (AMSANT) says the policy discriminates against people experiencing poverty, homelessness and mental ill health — particularly Aboriginal people, who make up a large proportion of those affected.

AMSANT Chief Executive Dr John Paterson said the NT has close to 6,000 people on the public housing waitlist and one of the highest rates of rough sleeping in the country — 13 times the national average.

One in five Aboriginal people in the NT is experiencing homelessness.

Dr Paterson said the dress code is "another example of a government unnecessarily punishing people instead of addressing the root causes of disadvantage in our communities".

"The Infrastructure Minister has justified this level of discrimination in the name of keeping bus seats clean," he said.

"In a jurisdiction with one of the highest homelessness rates in the country, this decision is not just elitist — it's shameful. This has nothing to do with public safety or hygiene. It's about exclusion."

Appearing on ABC Radio Darwin, Minister for Infrastructure and Logistics Bill Yan defended the policy, saying: "There has to be a level of hygiene and a level of dress to be able to get on that network. It's as simple as that."

Mr Yan said while some signs may have been updated recently, the hygiene rules have existed for a long time.

The Northern Territory Government's website states: "People with soiled clothing or items that may soil the bus or clothing of any passenger will not be allowed on the bus."

Critics argue the Country Liberal Party (CLP) government has continued to criminalise poverty since coming to power, pointing to a suite of tough-on-crime policies including stricter bail and alcohol laws, and the lowering of the age of criminal responsibility to 10.

Private security patrols have long been a fixture in Darwin, with long-standing concerns about alleged mistreatment of Aboriginal and homeless people.

Dr Paterson said the dress code sends a clear message: those doing it tough are not welcome.

Mr Yan denied the claim, telling the ABC: "If they're reasonably clean and tidy and not dirty and messy and going to stain the seats or have stuff that's going to break the seats or cut the seats, then they can get on the bus. There's no issues there."

"The driver is responsible for people on the bus, and they can determine who gets on or who stays on the bus, as well as the transit security officers," Mr Yan said.

However Dr Paterson said relying on "common sense" from bus drivers and security to decide who can and can't ride creates further risk.

"Public transport is a basic right for everyone in our communities — regardless of whether you can access washing facilities or afford stable accommodation," he said.

"Relying on 'common sense' from bus drivers and transit officers to apply this policy fairly is simply not good enough. It opens the door to subjective judgement, racial profiling and further discrimination — and it doesn't pass the fairness test for the public, who expect to use essential services, to catch a bus at the end of the day, without the threat of shame or exclusion."

Dr Paterson warned the policy may breach anti-discrimination laws and disproportionately affect people with intellectual disability, neurodivergence and mental health conditions.

"We should be supporting people — not making life harder with punitive dress codes that entrench disadvantage," he said.

"This is yet another example of the NT Government choosing punitive, divisive responses over real investment in the supports we actually need — safe housing, disability support, and culturally safe, community-led services that strengthen our communities and keep all people safe."