DUBLIN (Reuters) - An Irish Roman Catholic religious order has apologised unconditionally for the "physical and emotional trauma" its nuns inflicted on children raised in its orphanages and schools.

The Congregation of the Sisters of Mercy, founded in 1831 to care for the poor and uneducated, said it accepted unreservedly that many children had been hurt while in its care.

"We believe that you suffered physical and emotional trauma," the group said in a statement on Wednesday addressed to the survivors of the abuse.

"We express our heartfelt sorrow and ask your forgiveness. We ask forgiveness for our failure to care for you and protect you in the past and for our failure to hear you in the present."

The Sisters of Mercy were at the centre of a scandal which shocked Ireland in 1996, when a television documentary exposed the extent of abuse at one of their orphanages in Dublin in the 1950s and 1960s.

People raised there revealed how, as children, they were beaten with wooden chair legs and whipped with rosary beads. Badly behaved children were trussed up and hung from door frames as punishment.

The documentary prompted an apology from the Sisters but survivors dismissed it as hypocritical.

However, Thursday's statement went further.

"We have in the past publicly apologised to you," the Sisters said. "We know that you heard our apology then as conditional and less than complete. Now without reservation we apologise unconditionally to each one of you for the suffering we have caused."

Survivors groups welcomed the statement.

"Today a little bit of light has come. I have to state I admire their bravery," said Christine Buckley, the woman whose testimony formed the core of the 1996 documentary.

Dozens of cases of abuse at religious schools have come to light in Ireland in recent years as the country has, sometimes reluctantly, delved into its murky past.

The state formally apologised to victims in 1999 and set up a commission to compensate them for their suffering, but some say the commission is simply a way of keeping them quiet.

One survivor, 57-year-old Tom Sweeney, is currently camped outside the Irish parliament and has been on a hunger strike for three weeks in protest at the way his case has been dealt with.

"It seems that whatever these people are doing to us, they're just punishing us all over again and that has to change," he told Irish state television news. "I'll stay here and be taken away in a box if I have to."