The Irish Congress of Trade Unions (ICTU) has called for legislation to help protect women from known domestic abusers to be introduced in Northern Ireland.
'Clare's Law' was brought in across England and Wales two years ago following the death of Clare Wood.
The 36-year-old was murdered by her partner George Appleton who had a history of crime against women.
The Domestic Violence Disclosure Scheme (DVDS) allows victims or their friends or relatives to find out if a partner has a history of violence.
The ICTU, meeting in Derry, said it is important that women in Northern Ireland are afforded the same protections as women in other parts of the UK.
The mother of Jean Quigley, murdered at her home in Derry in 2008 by her partner Stephen Cahoon, has backed the call.
Emma McBride said her daughter did not know Cahoon had a history of violence against women.
"People would have been aware of who he is and what he was. People could have warned their children, warned their daughters," she told the BBC.
"If we only had have known what he was like, if he had been on some kind of list, maybe my daughter would still be here today."
