New research from the Dublin Rape Crisis Centre shows the high level of acquittals in rape cases.

The research, carried out by Senator Ivana Bacik, of Trinity College Dublin's Law Department, with the support of the DPP's office and the Civil Legal Aid Board, examined 40 of the 59 rape cases tried in the Central Criminal Court between 2003 and 2009.

It showed that in over 47 percent of cases the accused was acquitted. Just under one third of cases were successfully convicted, with the remainder either awaiting trial or concluding nolle prosequi.

In 70 percent of the cases the judge allowed the defence to question the victim's previous sexual history - under what's known as a Section 3 application.

Ms Bacik said the research showed judges were inclined to allow this - often prejudicial -evidence be heard on the grounds of a woman's alleged promiscuity in many cases.

She has called for further research to see what impact these legal procedures are having on the outcomes of rape trials.

The Director of Public Prosecutions, James Hamilton, told RTÉ News the findings were interesting and demanded further study before any changes to the law would be considered.

The Dublin Rape Crisis Centre held today's conference to mark its 30th anniversary. The centre says while a lot has been done to support victims of rape, many still fear the criminal justice system.

Criminologist Paul O'Mahony of TCD told the conference that fewer than one in forty cases of rape end up being appropriately punished.