The committee has found "up to 20 per cent of all non customs staff with access to sterile areas (at airports) have criminal convictions, and about half of these were serious convictions, including drug trafficking, assault and other misdemeanours".

This is a startling figure given staff in so-called "sterile areas" at airports, where they are behind the customs barriers and have access to passengers' luggage, are expected to hold an Aviation Security Identification Card.

Applicants for this card must undergo a criminal records check.

The Senate committee fears some staff, including cleaners and security guards brought in as subcontractors through specialist agencies, have access to sensitive areas without being vetted in the same way as people employed directly by the airports themselves or customs.

There are also fears that when vetting does occur it can be lax, prone to miss things and is not updated if an individual who was employed with a clean record suddenly acquires a criminal history.

While it is estimated one in six Australians, or about 16 per cent of the population, has a criminal record, one would not expect this to be directly reflected in an employment sector where a clean rap sheet is a "must have".

Leaving aside the possibility former offenders may be recruited by groups planning acts of terrorism or extortion, the greatest risk to the community from the presence of convicted criminals in these places is from drug trafficking, property theft, money laundering and the like.

While Schapelle Corby was markedly unsuccessful in her attempt to convince her Indonesian judges Australian baggage handlers had planted marijuana in her boogie board bag, that case did shine a bright light onto a murky subject.

There was a general consensus that while this had not happened in the Corby case, it was definitely a possibility.

Our major airports have now overtaken the nation's docks as Australia's primary gateways to and from the world. This makes them very attractive to the same types of groups who were keen to infiltrate the waterside workers 50 and 60 years ago to exploit opportunities to steal luggage and merchandise and to ship contraband in and out of the country.

These risks have been highlighted on numerous occasions over the last decade with the Australian Customs and Border Protection Service catching out at least eight of its own during a two year investigation into internal corruption from 2010 to 2012.

It was alleged large quantities of cash, drugs and drug precursors had been moved freely between Australia and South East Asia.

While it is true that former criminals should be given every encouragement to re-engage with the workforce, common sense dictates some jobs should be off limits. Working in a restricted area at an airport is one of these.