The Department of Foreign Affairs has toughened its travel advice for the USA three times in just over a month in response to the Trump administration's increasingly harsh border controls.
While DFAT has not changed the USA's overall rating from green, which means "exercise normal safety precautions", it has beefed up warnings about being detained at the border and requirements to carry identification while travelling within the country.
The series of changes in April and earlier this month came as Australian holiday travel to the US plunged after a crackdown in which border authorities detained and deported visitors and searched electronic devices.
Fears have also been stoked by images of masked agents from US Immigration and Customs Enforcement, or ICE, seizing people in the street and hustling them away.
In one high-profile case, the US sent El Salvadoran man Kilmar Abrego Garcia to a notorious prison in his native country and has so far refused to bring him back despite admitting he was deported by mistake.
Advice updated earlier this month
DFAT changed the language of the USA entry on the government's Smartraveller website on April 4 to increase the prominence of existing advice that entry requirements to the US are strict, that border authorities there "actively pursue, detain, or deport people who are in the country illegally" and that "officials may ask to inspect electronic devices, emails, text messages or social media accounts" and if travellers refuse they may be denied entry.
The advice was again updated on April 16 by adding a warning about a law forcing foreigners who are in the country for more than 30 days to register with authorities, together with instructions on how to check if they've been registered.
While the law was on the books before Mr Trump came back into office, he issued an executive order on January 20, "Protecting the American People Against Invasion", that demanded authorities tighten compliance with it.
DFAT's advice was again strengthened on May 6 to add a warning to would-be travellers of a new requirement that boarding domestic US flights now requires a passport or photo ID which meets US Department of Homeland Security requirements.
Australian travellers began avoiding the US even before DFAT changed its advice, but the downturn deepened last month.
Two weeks ago, Australia's biggest travel agency, Flight Centre, downgraded its profit forecast by up to $100 million, saying developments in the US "have exacerbated the volatile trading conditions experienced throughout the year".
Its chief executive, Graham "Skroo" Turner, told the ABC leisure travel from Australia to the USA was down by a "reasonably significant" amount of between 7 per cent and 10 per cent in the first three months of the year.
"But in April we saw a significant downturn in leisure travel of 16 per cent and business was down about 7 per cent, compared to the same time last year," he said.
Mr Turner said he expected the trend to continue.
"Some people don't like the idea of travelling to Trump country, they don't like his policies," he said.
"The other issue is that they're worried about some of those stories they've heard."
He said border rules were "still very strict" but little had changed for Australians, who are generally eligible for a visa waiver.
"People hear these sad stories of people being detained," Mr Turner said.
"It's probably been happening normally but people hear more of it now.
"The unsettled climate in business has affected us as well.
"We're pretty sure it'll be a short-term phenomena, particularly if Trump does come to bargains with more and more countries."
Warning for LGBTQIA+ travellers
Equality Australia has warned LGBTQIA+ people to reconsider travel to the US, particularly if the gender in their passport does not match the one they were assigned at birth or they have a history of activism.
Legal director Heather Corkhill said the organisation did "not expect the travel risks to diminish in the near future".
"LGBTIQ+ people are now very conscious of the risks, and some are choosing not to travel to the US while others are taking steps to mitigate the danger — such as deleting content on their phones or memorising phone numbers of loved ones and lawyers," she said.
"Even after arrival, travel within the US carries a growing level of risk with states across the country introducing hundreds of anti-LGBTIQ+ laws this year that restrict such things as bathroom access and correct gender markers."