SNP ministers are to sit down with leading Scots Tories to discuss taking swift action to ensure sex attackers cannot shake off monitoring and go underground, emerging later to attack again.

The issue was raised by Bill Aitken, the Conservative justice spokesman, last week during Alex Salmond's opening statement as First Minister. A promised meeting will take place soon to consider the proposals.

These include naming sex offenders who breach their conditions, tagging offenders and satellite tracking, and the possible introduction of lie detector tests, although ministers are understood to have doubts about the effectiveness of the latter.

Angelika Kluk's murderer, Peter Tobin, is an example of someone on the sex offenders' register who evaded police surveillance and went underground for almost a year, before emerging to kill the Polish student.

At the weekend, serial sex offender Morris Petch was recaptured by police after going on the run while on bail awaiting sentence for rape, another case which critics say prove the current system is not working.

A spokeswoman for the Scottish Executive said yesterday: "The First Minister said in parliament last week that he is very happy to meet with Bill Aitken to discuss the best way forward to crack down on sex offenders.

"The Scottish government is keen to reach a consensus on the matter. Ministers believe that a traffic light system, with the police and procurator-fiscal able to trigger a red alert' in a variety of circumstances, offers a positive way forward.

"But equally, they are very willing to discuss other similar proposals in the hope that the parliament can move forward together."

Mr Aitken, who will meet Mr Salmond and Justice Secretary Kenny MacAskill in the near future, said: "I think the majority view in the parliament is that something should be done in respect of the operation of the sex offenders' register, which is not working as we would have hoped. I think the vast majority of MSPs agree with that and I am hopeful that changes can be made."

Meanwhile, the ex-wife of convicted killer Peter Tobin has been interviewed as part of a police investigation into the disappearance of a teenager 16 years ago.

Vicky Hamilton, 15, went missing while waiting for a bus in Bathgate, West Lothian, in February 1991.

Last week it emerged Tobin, the man convicted of raping and murdering Polish student Angelika Kluk, lived less than a mile away from where Vicky was last seen.

Lothian and Borders Police had said they planned to search his former house in Bathgate.

His ex-wife, Cathy Wilson, told the Sunday Mail newspaper she had been questioned by police and that they had taken a DNA sample.

Ms Wilson, 37, said she left Tobin, and the Bathgate house they shared, in January 1991, a month before the teenager went missing. She said: "The police contacted me. They wanted to know about the house, the layout, how many times we decorated and when we decorated. They took a DNA sample of my saliva."

A source close to the investigation said that everyone who had ever lived in the house was being interviewed and that Ms Wilson had not been singled out.

The source said: "It's for elimination purposes. We want to build a picture of who has lived in the house and will be speaking to many people."

Police recently reopened the case of the teenager, who had been making her way home to Redding, near Falkirk, after visiting her sister.

During the investigation into Ms Kluk's murder it emerged that Tobin, 60, lived for a time in Bathgate.

He was found guilty of raping and murdering Ms Kluk in September last year then dumping her body underneath St Patrick's Church in Anderston, Glasgow.