Australians travelling to the US next week could be blocked from boarding their flights should they fail to comply with little-publicised new entry requirements.
The new rules are part of the US Government's attempts to strengthen border security after the attacks of September 11, 2001, but there appears to be confusion in Australia about who will enforce them.
Australians flying to the US can now get a visa waiver allowing them to stay for up to 90 days, but from next Monday passengers must first apply online for electronic travel authorisation.
Those who don't get the Electronic System for Travel Authorisation (ESTA) won't be allowed to board their flight, the US Department of Homeland Security website says.
But it was not clear who would stop unauthorised Australians from boarding.
"They should be checking them at the airport prior to travel," said Brad Niemann, vice-consul at the US consulate in Sydney.
"From what I understand they are in a position to [access information about who has been successfully authorised]."
An Australian Customs Service spokeswoman said customs officers would not be checking passengers had completed the authorisation process. This would be done by the airlines, she said.
But Qantas said the latest information it had was that airlines were not responsible for the checks.
"US authorities advised the International Air Transport Association (IATA) last year that during the initial implementation of ESTA from January 12, airlines would not be required to confirm a passenger had obtained the travel authorisation," a Qantas spokeswoman said.
However Qantas was upgrading its check-in systems to meet any future US requirements, she said.
Qantas check-in staff would also give passengers travelling to US information about ESTA that had been provided by the US government, she said.
More than 40,000 Australians travelled to the US each month, according to the Australian Bureau of Statistics.
If the authorisation rules are successfully enforced at Australian airports, there could be ugly scenes amid fears few travellers know about the new requirements.
Airlines have expressed a fear of airport chaos when the authorisation becomes mandatory on January 12 (it has been operating on a voluntary basis since August last year).
"Unless the message gets out really quickly, there's a growing concern that people will turn up for their holiday ... and won't be able to get on the plane," an airline spokesman, who asks not to be named, told The Sun-Herald last October.
"The airline staff won't be able to fix it."
But Mr Niemann said the authorisation process was simple and instantaneous, and could even be done at the airport should a traveller turn up for a flight without having completed the online process.
"Anyone can fill it out for you. As long as you can call someone who can access the internet, or even if you get on a computer at the airport [you'll be fine]," he said.
"From what I've seen 99 per cent of people get immediate approval ... you could even do it with a BlackBerry."
About 300,000 were approved through the online process by November last year with less than 0.5 per cent of applications refused, US officials say.
Mr Niemann said the online authorisation asked for only basic information - for example passport details, where a passenger will stay in the US, if they are involved in terrorism or genocide - and was similar to the I-94 form travellers filled out on arrival in the US.
He was also hopeful most travellers were aware of the new rules.
"It's been up and running, but not mandatory, for about five or six months now and we've been [communicating] with the travel community so are hopeful the message has gone out to travel agents that their customers need to do this."
The Australian Government's travel advice website, Smartraveller, outlines the new entry requirements for travellers.
The Government's advice has also been distributed to travel agents via the Australian Federation of Travel Agents, whose website has fact sheets about the new rules for its members.
Major airlines including Singapore Airlines and Qantas also have information about the scheme on their respective websites.
Travellers are recommended to apply online at least 72 hours before departure.
Approved applications are valid for up to two years, or until the travellers passport expires, and are valid for multiple entries into the US.
* To apply for the Electronic System for Travel Authorisation go to https://esta.cbp.dhs.gov
* More information contact the US embassy, Canberra, on (02) 6214 5600, or see canberra.usembassy.gov/consular/visas
- with AP