Sinn Fein leader Mary Lou McDonald has said the new Garda Commissioner must address the concerns of victims and survivors of loyalist attacks.
Ms McDonald said her party had confidence in Drew Harris but he needed to take into account the feelings of victims and survivors.
The party president made the comments on Mr Harris’s first day in his new role. He was attested as the new commissioner in Dublin on Monday.
Some survivors and the families of victims of loyalist attacks expressed concerns when Mr Harris was appointed.
Questions were raised over his suitability because of his experience in the RUC and the Police Service of Northern Ireland (PSNI).
During his time with the PSNI, Mr Harris worked closely with MI5.
As Garda Commissioner he will be in charge of state security as well as day-to-day policing.
The Sinn Fein leader said she did not want to see the new commissioner fail but he needed to address the “legitimate” concerns of families.
“We have to get policing right,” Ms McDonald said.
“I want the new commissioner to succeed, I don’t want him to fail.”
Ms McDonald referred to the Dublin-Monaghan bombing and the Miami Showband massacre which involved allegations of collusion between loyalist organisations and the RUC.
“At the core of accountable, responsive policing is public confidence,” she said. “This is a legitimate issue.”
She added that she had experience of working with Mr Harris in Northern Ireland and she looked forward to engaging in a “very constructive” working relationship.
“I want there to be public confidence in the new commissioner and I firmly believe for that to happen then I think that he has to address the concerns and experiences of those families,” she said.
“It’s absolutely essential and it’s hard to imagine when the government signed off on the decision, this particular appointment, it’s hard to imagine that it didn’t occur to them that these issues would arise in respect to the Dublin and Monaghan families or the Miami Showband.
“This is a very serious matter. I don’t think it is real to brush it off.”