Six people have been arrested in a nationwide string of police swoops in connection with investigations into human trafficking, broadcaster Nos reports.

In total, the papers of around 100 prostitutes were checked. The raids involved 220 police officers and took place on Wednesday afternoon and evening.

The raids were triggered by an investigation into home-based prostitution via internet advertising. In a number of suspicious cases, police made an appointment with the prostitute concerned. The meetings were set up in private homes, hotels and holiday parks.

According to the Volkskrant, police had been monitoring 500 websites with names like kinky.nl, citygirl.nl en verhit.nl for potential leads.

The raids have also provided good information for ongoing investigations, Nos says. In addition, it will allow local councils to take action against unlicenced brothels.

More details about the raids and the results are due to be published later on Friday, the Volkskrant said.