The Swiss authorities have called for more action to be taken against human trafficking at the country's first nationwide conference on the issue.
The move comes on the same day that non-governmental organisation Terre des Hommes said that tougher laws on people smuggling were needed in Switzerland.
The Swiss Coordination Unit against the Trafficking of Persons and Smuggling of Migrants, a section of the Federal Police Office, said on Thursday that cases of trafficking were hard to detect.
"The victims, who are traumatised and often illegal residents, rarely file a complaint against the smugglers because they don't know their rights or fear for their safety," said Stephan Libiszewski, head of the unit.
"That's why it's up to the authorities to do more to combat smuggling of people."
The unit has been operational since 2003. Its main task is to set up a network that provides better protection for victims and encourages more prosecution of criminals.
It also organised the first ever national conference on human trafficking, with over 130 specialists from all over the country, which took place in the Swiss capital, Bern, on Thursday.
The unit used the occasion to present a practical guide for all those dealing with cases of people smuggling.
It said that victims had to feel confident enough to come forward with information and that one way of doing this would be to grant temporary residency.
Protection and social aid can also positively influence the outcome of a smuggling case. But the unit says that the cantons, which are responsible for policing their own backyard, need to set up working groups to coordinate these measures.
Libiszewski added that the Swiss foreign ministry also contributed to the fight against human trafficking. Its services can identify potential victims when it gives out visas in countries such as Thailand and Brazil or in eastern Europe.
In all, only a few people are charged with human trafficking in Switzerland each year, usually around 30 to 40. And just three to four receive are actually convicted, which Libiszewski says is totally unsatisfactory.
There are an estimated 1,500 to 3,000 victims of trafficking in Switzerland annually and this figure only covers people who were smuggled in for the sex trade.
Terre des Hommes, which defends children and women, said at a separate event on child trafficking on Thursday that Switzerland needed tougher legislation against people smuggling.
"Child smugglers should be intercepted and convicted in Switzerland, no matter what their nationality is and where they committed their crimes," said Muriel Langenberger of Terre des Hommes Switzerland.
"It is the only way to make sure we will not serve as a refuge for traffickers."
Swiss laws on human trafficking are up for revision and should include amendments on organ trafficking and forced labour. It is then expected that Switzerland will sign the United Nations protocols on migrant trafficking and children's rights.
Terre des Hommes said it was pleased with the planned changes, but added that it wanted harsher sentencing. Child smugglers should be given a minimum one-year prison sentence.
The House of Representatives should vote on the revised legislation during its next session.
swissinfo with agencies
The Swiss penal code defines human trafficking as the trade in people, especially women, who are then forced into prostitution.
According to the United Nations' new definition of the term, it also includes other forms of trade in human beings including forced servitude and other exploitive forms of labour as well as the trade in human organs.
This new definition is to be incorporated into the Swiss penal code.