Andrea Bauer, a spokeswoman for Migros-Aar, which owns the Bernaqua waterpark, confirmed to daily 20 Minuten that clients had reported a drone above the exterior ‘relaxation’ area outside the nude sauna on several occasions.

“A customer told a lifeguard, who warned the security guards,” she said.

It’s currently not known whether the drone had a camera attached, Bauer added.

It’s not the first time such an incident has happened, she said, adding that the park is taking the situation very seriously.

“The people who visit that area [of the waterpark] are naked or wearing few clothes. Protecting their privacy is therefore all the more important.”

The park has informed the police, confirmed Bauer, since flying a drone over a crowd is illegal in Switzerland without specific authorization.

The Bernaqua waterpark is attached to the Westside shopping centre on the outskirts of Bern.

It has two sauna zones – one for women-only and one mixed – both of which are nudist.

Earlier this year the University of Neuchâtel launched a three-year study into the impact of drones on life in Switzerland, aiming to consider issues related to privacy, individual freedom, security, terrorism and the growing digitalization of daily life.