After a series of attacks in Europe since 2015, Switzerland adopted the law last year to make it easier for the police to monitor and restrict the movement of potential offenders, including children as young as 12.
Opponents succeeded in putting the law to a referendum on June 13, but opinion polls show about two-thirds of voters intend to back the law, prompting experts to speak up in a final attempt to stop it.
“When you set up a system in which the federal police initiates and decides without a judicial review at the outset, it`s a Frankenstein brought to life,” Philip Jaffe, psychology professor and member of the United Nations committee of the rights of the child, told Reuters.
Under the law, restraining orders or travel bans can be imposed from the age of 12, house arrest from the age of 15. All measures can be contested in court.
The government says the measures are needed to prevent cases like the one of 15- and 16-year-old siblings who went to Syria in 2014 and were later convicted of supporting the Islamic State.
Jaffe said, however, that going after children too hard could radicalise them and innocents targeted by mistake could be psychologically damaged.
Before the law was adopted, around 60 law professors warned it paved the way for arbitrary decisions. United Nations experts said it violated human rights standards.
“The police and the secret service are our watchdogs, it`s their job to be aggressive. That`s why you have to keep them on a leash,” said Nils Melzer, the UN special rapporteur on torture.
He said the sharing of lists of potential terrorists with other countries could lead to individuals travelling abroad being imprisoned or even tortured.
The federal police said no lists will be established based on the new law.
It already compiles a terrorism database which can, in some cases, be shared with foreign authorities, but it only contains information on people involved in criminal proceedings.
In an emailed statement, the Swiss justice ministry and the federal police said social, integration and therapeutic measures were the first choices when dealing with potential terrorist offenders.
Radical opinions alone would not expose an individual to measures under the law, they said, as there had to be “concrete and current indications the person would commit a terrorist act.”
The Federal Intelligence Service said in November it was aware of 49 “risk persons” presenting a threat to Swiss security and was monitoring 690 users of jihadist websites.