Suspected benefit fraudsters will facelie-detector tests in a Whitehall initiative designed to catch out cheats claiming cash they are not entitled to.

The Government is preparing to test hi-tech voice analysis developed by the security industry in Israel and the United States, to catch out claimants who are not telling the truth.

The lie-detector technology measures stress, hesitation and other indicators of anxiety in a person's voice. Ministers say it could help identify people falsely pretending to be single parents or fraudulently claiming benefits. False claims cost the taxpayer pounds 3bn a year.

Civil servants have been talking to insurance companies which use the technology to combat fraud about the most effective way to test voice analysis' it could end up being used in telephone conversations or one-to-one interviews.

The prospect has alarmed civil liberties campaigners who say lie detectors must be regulated and should not be used without the claimant's knowledge.

James Plaskitt, the work and pensions minister, admitted in questions from the Tories that he was considering how to pilot the technique. David Ruffley, the shadow minister for welfare reform, said he thought it could be a "valuable tool" but warned it should be used with caution to avoid deterring genuine claimants.