Police in the North have made their first arrest under the new offence of paying for sex.
The North banned payment for sexual services earlier this year.
PSNI Chief Constable George Hamilton said a man had been detained during a raid on a suspected brothel.
He gave only brief details of the arrest, which happened last month, as he addressed members of his oversight body – the Northern Ireland Policing Board - in Belfast on Thursday.
The law change was championed by Democratic Unionist Assembly Member Lord Morrow. It has been hailed by Christian groups but denounced by prostitutes’ representatives.
Paid-for consensual sex had previously been legal in Northern Ireland although activities such as kerb crawling, brothel keeping and pimping were against the law.
The ban has seen the North implement a prohibition similar to the model in Sweden.
The law was among a number of clauses in a private members’ bill tabled in the Stormont Assembly by Lord Morrow. It became the Human Trafficking and Exploitation Act 2015 in January.
Mr Hamilton told the Policing Board: “Detectives from our human trafficking team conducting a brothel search and arrested a man for paying for sexual services – the first such arrest under Section 15 of the Human Trafficking and Exploitation Act 2015.
“Three females were also arrested and interviewed for keeping a brothel.”
The PSNI said no further details on the operation, including the location, were being made public.