As the missing Malaysia Airlines flight focused international attention on passport fraud, Carl Ungerer, an independent security consultant and former adviser to former foreign affairs minister Bob Carr, said there was a thriving market for stolen and doctored documentation in south-east Asia.

Ramzi Yousef, who was later convicted in connection with the 1993 World Trade Centre bombing, planted a bomb on a Philippine Airlines flight in 1994, killing one passenger but failing to bring down the plane.

He used a stolen Italian passport - a similar situation to the stolen Italian and Austrian passports used by two passengers in boarding the Malaysia Airlines flight MH370.

Dr Ungerer said such fraud was more difficult today but the lapse by Malaysian immigration officials highlighted the deep flaws remaining in the international system.

''At least one of the passports was stolen 18 months ago and reported and he'd actually acquired a new passport and was flying on it,'' he said. ''So, if the systems can't pick up something like that, then there's something seriously wrong somewhere along the chain.''

The fact that US officials - and, most likely, Australian officials - had rushed to examine the failure showed their concern, he said.

Interpol expressed frustration, revealing passengers flew 1 billion times last year without having their passports checked against the international agency's database.

''Interpol is asking why only a handful of countries worldwide are taking care to make sure that persons possessing stolen passports are not boarding international flights,'' said Ronald Noble, the agency's secretary-general.

A spokesman for Immigration Minister Scott Morrison said Australian border officials used ''a range of systems to verify the legitimacy of travel documentation'' - including the Interpol database.

''The Department of Immigration and Border Protection performs document alert checks and identity checks on all passengers at visa grant and upon entry or exit,'' he said. ''Relevant Interpol holdings form part of those checks.''

A security firm chief who introduced biometric surveillance to airports throughout the Asia-Pacific region after the September 11 attacks said Australia lacked checks for outgoing passengers, which meant a convicted terrorist was able to flee in December.

''It's a very big hole,'' said Roger Henning, Homeland Security Asia-Pacific's chief executive.

Experts say Malaysia has a relatively good security record. But the lapse has raised questions, especially after the country's Interior Minister reportedly said the two men had ''Asian facial features''.

Neil Fergus, head of security firm Intelligent Risks, which has previously reviewed aviation security for the federal government, said that it would be ''incredibly alarming'' if the men had managed to alter the photos on the passports.

''If people can doctor a photograph on what is regarded as a good, standard tamper-proof passport, that has repercussions for international aviation,'' Mr Fergus said.

Australia provides ''airport liaison officers'' to Kuala Lumpur International Airport who check passengers boarding flights to Australia, as well as training for the Malaysian officials.

''Australia at least has some concerns about Malaysia's passport control and document examination,'' a source said.