Sinn Fein's Martin McGuinness has said he does not believe a new threat against the family of Robert McCartney comes from republicans.
McCartney sisters are seeking justice for their murdered brother
The murder victim's family have said they have been told by police of a threat from republicans.
The 33-year-old was fatally stabbed outside a Belfast pub. His family have maintained IRA members were involved.
The family said the threat seemed more sophisticated than a previous one, which came from "criminal elements".
Mr McCartney's sister, Catherine, said on Friday the PSNI had confirmed the latest threat was from republican sectors.
"This threat implies that republican elements are going to take action against the McCartney family if they continue to discredit the republican movement," she told the Press Association.
Martin McGuinness does not believe republicans are behind the threats
The family said they would be seeking more details about the nature of the threat from the PSNI.
Earlier this month the family blamed republicans for a threat to burn them out of their homes and businesses.
Police warned them of it, saying "criminal elements" were behind it.
On Saturday Mr McGuinness, Sinn Fein's chief negotiator, said he took a poor view of anyone threatening the sisters or fiancee of Mr McCartney.
"Of course if threats are being issued against the McCartneys in all likelihood they are being issued by people who are totally opposed to republicanism, or even people who have brought republicanism into disrepute in the course of recent times," he said.
"I take a very dim view of anyone issuing any threats against the McCartneys.
"What we have to understand here is that the McCartneys have a just cause, they are seeking truth and justice for the murder of their brother."