Irish prison officers have carried out extensive searches of the Dóchas Center, the state's only designated woman's prison, as part of their inquiry into how photographs of female prisoners dressed in lingerie appeared in a Sunday newspaper.

Prison officials conducted the searches yesterday at the woman's prison which is part of the Mountjoy complex in Dublin city. About 150 inmates were forced to leave their houses on the site and placed in a gym, while all the area's were fully searched.

The photographs which appeared in last weekend's Sunday World showed some of the female prisoners dressed in lingerie and assuming suggestive poses. Two of the women who appeared in Sunday's newspaper were transferred from the Dóchas Center to the female wing of Limerick Prison on Sunday.

It is understood that yesterday's large scale search of the entire woman's wing is unprecedented. Prison officers are believed to have been searching for camera phones as well other contraband such as drugs and weapons.

The Dóchas Center has an operational capacity of 105, but in recent months due to overcrowding it has been holding 150 female inmates.

Earlier this year the former governor Kathleen McMahon stepped down after her fears of "self-mutilation, bullying, depression and lesbianism" within the prison were not investigated by authorities.

The female facility was unique when it was opened as every prisoner had her own room. However in the past year reports have suggested that up to five inmates may now share a room.