The Australian | October 25, 2011
By Steve Creedy

BETWEEN 20 and 40 per cent of the 23,500 scans conducted during trials of the controversial body scanner technology in Sydney and Melbourne airports gave a potential false alarm.

The Office of Transport Security is combing through the results of the trials in August and last month to see whether it had procedures right and whether the technology was giving an actual alarm or false alarm.

It is also looking at whether software updates released since the trials will make a difference and whether the machines were set off by sweat.

Office of Transport Security executive director Paul Retter told a recent Senate estimates committee hearing that the technology was improving "on a weekly and monthly basis".

The Australian tests are an improvement on German trials, in which an alarm was set off in seven out of 10 cases.

The government has not yet made a decision on the scanners, but Mr Retter said his likely recommendation would be for a progressive rollout at eight international airports.

"We would envisage that the rollout will start to occur from the early part of 2012," he said.

Asked about media reports the scanner could not effectively detect home-made explosives, Mr Retter said body scanners in his view offered "the best chance in the world today to detect explosives, including home-made explosives".

Airlines have also been concerned the machines could cause flight delays, but Mr Retter said the time spent in the scanner was only 1.5 to 2.5 seconds.

He said the speed at which cabin baggage could be cleared remained critical with both body and walk-though scanners.