A full range of measures - including satellite tracking and lie detectors - could be brought to bear on sex offenders who go into hiding, Justice Secretary Kenny MacAskill said yesterday.

He said these technical measures would be looked at, as well as already agreed methods such as posting identities and photographs of those who abscond or breach conditions.

But he rejected Labour's call for DNA samples for all crime suspects to be kept by the police. "If what you are asking is anybody who is charged with a very minor offence and has a routine sample taken from them should have their DNA retained, then I think that takes the balance too far," he said.

Conservatives approached ministers in the wake of the Angelika Kluk case; it emerged Peter Tobin, the convicted sex offender who raped and murdered the Polish student, had been on the run for almost a year before carrying out the killing.

Mr MacAskill said the problem lay with a small number of offenders, saying: "They are few but they are predatory, devious and highly dangerous."

The previous administration had already agreed pictures of those who breached the terms of the sex offenders' register could be published on the internet.

Mr MacAskill said: "Today, I reaffirm that if a sex offender goes missing and fails to comply, then the response will be tough."

He told MSPs that would include, where appropriate and subject to the guidance of the police and the Crown Office, publishing photos on the internet and elsewhere.

He added: "We will look, with our enforcement agencies, at the opportunities offered by new technology such as satellite tracking and polygraph testing."

Labour's community safety spokesman, Paul Martin, said it was vital the necessary resources were put in place for the measures proposed.

Conservative justice spokes-man Bill Aitken described his party's proposals as common sense and welcomed the support they had received from other parties. He said: "We are talking about dealing with people who have already been convicted, who have already been sentenced for this type of offence."

Mr Aitken also called for a US-style "most wanted list" to be compiled. "Because these are dangerous people, their pictures should be up on a website, their pictures should be on television."

Susan Matheson, chief executive of Sacro, the charity that works with offenders after their release into the community, said a balance must be found. She said: "There has to be a balance between danger and what might amount to harassment of offenders."

Victims of the devious and dangerous
The murder of Jessica Chapman and Holly Wells in Soham in 2002 by Ian Huntley led to greater information sharing between police and other authorities to ensure sex offenders were unable to take up jobs working with children. Calls for a "Mark's Law" - similar to Megan's Law in the United States - to be introduced in Scotland were made after Mark Cummings, pictured, was killed by known sex offender Stuart Leggate, who lived in the same tower block as the boy in Royston, Glasgow. They were eventually rejected by the Scottish Executive amid fears they could drive sex offenders underground. In one of Scotland's most notorious child murders, nine-year-old Scott Simpson was lured away from an Aberdeen playground by convicted paedophile Steven Leisk and killed in July 1997.