In total, around 5,000 unaccompanied migrants aged under 18 at the time of arrival currently live in Switzerland, said the broadcaster, quoting the Swiss migration office (SEM).
However after saying they want to claim asylum, many then flee the official reception centres and disappear from the authorities' radar.
In total 539 young migrants went missing in 2016 – a figure that includes 81 who were aged over 18 but who are counted as minors because they claimed asylum when they were under 18.
The vast majority – 324 – were aged 16-17, while 134 were in the age bracket 6-15.
So far this year 310 minors have dropped off the SEM's radar.
Speaking to the broadcaster, Valentina Darbellay of Swiss child aid agency Terre des hommes said many of these young people risked ending up victims of trafficking or as delinquents.
Reporting practices vary from canton to canton, meaning young migrants are not always reported missing as non-migrant children would be, she said, adding that this discrimination was “shocking”.
Lukas Rieder, a spokesman for the SEM, recognized that young migrants going missing was a problem, but said the elevated numbers last year were proportional to the number of young asylum seekers now living in Switzerland.
The SEM intends to work with the canton of “harmonize” practices across the country, he told RTS.
The issue does not only concern the underage.
Last September the SEM confirmed that in the previous three months between 20 and 40 percent of asylum seekers had fled reception centres after claiming asylum.
A report in the media suggested that in some areas of the country up to 90 percent of asylum seekers flee while awaiting the outcome of their application.
The SEM said at the time that most of those who disappear from Swiss reception centres are thought to be heading for Germany.
As a result, there's nothing to suggest that there are more illegals living in Switzerland.
Under the rules of the Dublin agreement, refugees are only allowed to enter Switzerland if they say they want to claim asylum here.
Anyone who does not state their intention to claim asylum in Switzerland is refused entry and must return to the first European country they entered.