TOKYO: Japanese police are considering introducing lie detector tests as part of their recruitment process to try to weed out possible sex pests and other potential criminals, a newspaper reported Tuesday.

The National Police Agency plans to use polygraphs only on those who consent to taking the tests, to avoid being accused of invading privacy, the Asahi Shimbun said.

Recruiters plan to analyse reactions from candidates after they are asked for their thoughts on paedophilia or their interest in molestation, the daily reported.

Polygraphs measure and record phsyiological reactions, such as heart rate or breathing, while the subject is asked questions. Advocates say the act of telling lies causes bodily responses that cannot easily be controlled.

The move has been mooted because "scandals were repeatedly committed by people who apparently lacked the skills required of policemen", a senior police official was quoted by Asahi as saying.

Competition to join Japan's police force is stiff, with only 14,700 out of nearly 126,000 candidates passing exams in the year to March 2012, to become locally-recruited officers.

At the same time, the number of disciplinary actions against officers surged from 242 in 2009 to more than 400 in 2012, the newspaper said.

Among them is a policeman who was dismissed for attempted rape in January last year, who is now suspected of having had sex with minors all through his adult life.

Following initial examinations, all successful applicants must graduate from a police academy before serving in the 293,000-strong force in low-crime Japan.

Immediate police confirmation of the news report was not available.