Two others, a man and a woman, remain in custody at Tullamore and Carlow Garda Stations.
Another man was arrested in the Co Carlow area this afternoon.
A total of ten people were arrested yesterday.
Four women and three men were arrested following raids on brothels in Cavan, Drogheda, Athlone, Mullingar, Sligo, Kilkenny, Enniscorthy, Newbridge, and Waterford.
Six other locations in the Carlow area were also searched, including the homes and offices of a number of professional individuals.
The raids followed an international investigation into human trafficking which involved gardaí, the PSNI and the British Serious Organised Crime Agency.
As well as the seven people held by gardaí, a man was arrested by the PSNI in Co Down and a man and a woman were detained by police in Wales.
The PSNI also conducted a number of covert inquiries at several locations in Northern Ireland being used as brothels by a criminal gang, organised through the internet.
