Mandatory testing with a polygraph, or lie-detector, should be introduced to monitor convicted sex offenders undergoing police supervision, according to university research commissioned by police chiefs.

The study by psychologists at the University of Kent, published on Wednesday, argued that compulsory testing could reduce the risk to the public and target “all categories of risk effectively”.

Published by the university’s Centre of Research and Education in Forensic Psychology, it was carried out for the National Police Chiefs’ Council (NPCC).

Over the past decade, police and probation officers have been piloting the use of lie-detector tests on sex offenders released on licence.

The Ministry of Justice backed the use of polygraph machines following a successful trial in 2012, which concluded that it “increased the chances that a sexual offender under supervision in the community will reveal information relevant to their management, supervision, treatment or risk assessment”.

However, the technology has been criticised as unreliable. An exhaustive review of the scientific evidence by the US National Research Council in 2003 indicated that although the polygraph performs above chance, studies had found wildly differing accuracy rates.

Lie-detector tests remain inadmissible in UK courts because of their unreliability. Many experts said while they can detect physiological changes, they are not scientifically validated as reliable measures that someone is lying.

The University of Kent report looked at evidence from about 800 individuals subjected to polygraph testing who were either “supervisees” convicted of sexual offending, suspects under investigation for online sexual offences, or those applying for removal of their notification requirements.

The study said: “Introducing mandatory polygraph testing of those convicted of sexual offences undergoing police supervision or applying for removal of notification requirements would be the most effective use of polygraph testing.

“Mandatory testing would eliminate refusals to volunteer for initial or subsequent polygraph tests, maximise numbers of people making [risk-relevant disclosures] RRDs, and maximise RRDs across time. It is also supported by the public and by offender managers.”

It added: “Findings across all police areas suggest that polygraph testing increases RRDs … Polygraph testing, regardless of whether voluntary or mandatory, elicits more information relevant to risk.”

However, it noted that “unlike offender managers involved in supervision and applications, investigative officers did not view the polygraph as especially useful with suspects, because it cannot be used as evidence.”

Polygraph operators also complained that “testing in noisy police stations exacerbates the challenges associated with testing and may impact results.”

The NPCC’s lead for the management of sexual and violent offenders, chief constable Michelle Skeer, said: “We will give this research careful consideration alongside others in policing and the Home Office.

“Policing in the UK has some of the most advanced and effective tools in the world to manage registered sex offenders and every day officers effectively manage the risk posed to the public by such people. This will always be a complex area of work for police and we continue to look at innovative ways, tools and technologies to keep people safe.”