Constant minitoring: From the time travellers book tickets, chekc are taking place.

Constant minitoring: From the time travellers book tickets checks are taking place. Photo: Peter Braig

Travellers on stolen passports like those used to board the vanished Malaysian Airlines flight are highly unlikely to get into Australia undetected, according to experts and an analysis of immigration procedures.

Roger Henning, head of Homeland Security Asia/Pacific, said despite stolen and forged documents being a multimillion business in Thailand, ''the likelihood of someone getting into Australia on a stolen passport is minute''.

Another security expert, Carl Ungerer, said: ''I am very confident Australian officials would have picked up the fact that these were fraudulent passports. I think they would have been caught long before they got on the plane.''

"Australiajn officials would have picked up the fact that these were fraudulent passport": Carl Ungerer, security expert.

"Australian officials would have picked up the fact that these were fraudulent passports": Carl Ungerer, security expert.

Australia uses a ''movement alert list'' which includes its own intelligence holdings of about 1 million entries or individuals, according to a source familiar with the issue. The list also draws on data provided to Australia from overseas, including Interpol's stolen passports database.

''Travellers are being checked the whole way through the process, from the time of their application - online or in person - to the boarding of their flight … to the primary line at the international airport at which they land,'' the source said.

European passport holders such as Austrians and Italians - the passports used to board MH370 - are considered low risk. But they must nonetheless apply for an electronic ''eVisitor'' authority online before they travel to Australia.

This automatically checks them ''against security and immigration risk'' data, according to the Immigration Department's latest quarterly report on visitor visas. Any of 39 million stolen passports registered with Interpol would show up immediately.

About 95 per cent of Austrians and Italians are approved automatically after this electronic check - without an immigration official even having to look them over. Most of the rest are approved quickly by an officer.

If the stolen passport was not registered on any database, the fraudulent holder would still have to get past immigration officers who ''are pretty good at profiling people … looking for any sign of agitation'', said Mr Henning.

Every person who stands at passport control to get into Australia has their face analysed - about 1500 to 1600 features - by facial recognition software to check them against the faces on the movement alert list.

Neil Fergus, head of the firm Intelligent Risks, says it is ''extremely complicated and difficult to create a forgery of an Australian passport''. On top of this, there are ''airport liaison officers'' at about 18 high-traffic and high-risk airports.